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Cheng J, Kolba N, Tako E. The effect of dietary zinc and zinc physiological status on the composition of the gut microbiome in vivo. Crit Rev Food Sci Nutr 2024; 64:6432-6451. [PMID: 36688291 DOI: 10.1080/10408398.2023.2169857] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Zinc serves critical catalytic, regulatory, and structural roles. Hosts and their resident gut microbiota both require zinc, leading to competition, where a balance must be maintained. This systematic review examined evidence on dietary zinc and physiological status (zinc deficiency or high zinc/zinc overload) effects on gut microbiota. This review was conducted according to PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) guidelines and registered in PROSPERO (CRD42021250566). PubMed, Web of Science, and Scopus databases were searched for in vivo (animal) studies, resulting in eight selected studies. Study quality limitations were evaluated using the SYRCLE risk of bias tool and according to ARRIVE guidelines. The results demonstrated that zinc deficiency led to inconsistent changes in α-diversity and short-chain fatty acid production but led to alterations in bacterial taxa with functions in carbohydrate metabolism, glycan metabolism, and intestinal mucin degradation. High dietary zinc/zinc overload generally resulted in either unchanged or decreased α-diversity, decreased short-chain fatty acid production, and increased bacterial metal resistance and antibiotic resistance genes. Additional studies in human and animal models are needed to further understand zinc physiological status effects on the intestinal microbiome and clarify the applicability of utilizing the gut microbiome as a potential zinc status biomarker.
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Affiliation(s)
- Jacquelyn Cheng
- Department of Food Science, Cornell University, Ithaca, New York, USA
| | - Nikolai Kolba
- Department of Food Science, Cornell University, Ithaca, New York, USA
| | - Elad Tako
- Department of Food Science, Cornell University, Ithaca, New York, USA
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2
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Miano A, Rychel K, Lezia A, Sastry A, Palsson B, Hasty J. High-resolution temporal profiling of E. coli transcriptional response. Nat Commun 2023; 14:7606. [PMID: 37993418 PMCID: PMC10665441 DOI: 10.1038/s41467-023-43173-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2023] [Accepted: 11/02/2023] [Indexed: 11/24/2023] Open
Abstract
Understanding how cells dynamically adapt to their environment is a primary focus of biology research. Temporal information about cellular behavior is often limited by both small numbers of data time-points and the methods used to analyze this data. Here, we apply unsupervised machine learning to a data set containing the activity of 1805 native promoters in E. coli measured every 10 minutes in a high-throughput microfluidic device via fluorescence time-lapse microscopy. Specifically, this data set reveals E. coli transcriptome dynamics when exposed to different heavy metal ions. We use a bioinformatics pipeline based on Independent Component Analysis (ICA) to generate insights and hypotheses from this data. We discovered three primary, time-dependent stages of promoter activation to heavy metal stress (fast, intermediate, and steady). Furthermore, we uncovered a global strategy E. coli uses to reallocate resources from stress-related promoters to growth-related promoters following exposure to heavy metal stress.
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Affiliation(s)
- Arianna Miano
- Department of Bioengineering, University of California San Diego, 9500 Gliman Dr, La Jolla, CA, USA.
| | - Kevin Rychel
- Department of Bioengineering, University of California San Diego, 9500 Gliman Dr, La Jolla, CA, USA
| | - Andrew Lezia
- Department of Bioengineering, University of California San Diego, 9500 Gliman Dr, La Jolla, CA, USA
| | - Anand Sastry
- Department of Bioengineering, University of California San Diego, 9500 Gliman Dr, La Jolla, CA, USA
| | - Bernhard Palsson
- Department of Bioengineering, University of California San Diego, 9500 Gliman Dr, La Jolla, CA, USA
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet, Building 220, 2800 Kgs, Lyngby, Denmark
| | - Jeff Hasty
- Department of Bioengineering, University of California San Diego, 9500 Gliman Dr, La Jolla, CA, USA
- Department of Molecular Biology, School of Biological Sciences, University of California San Diego, 9500 Gliman Dr, La Jolla, CA, USA
- Synthetic Biology Institute, University of California San Diego, 9500 Gliman Dr, La Jolla, CA, USA
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3
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Barnett JP. Transcriptional Response of Burkholderia cenocepacia H111 to Severe Zinc Starvation. Br J Biomed Sci 2023; 80:11597. [PMID: 37822354 PMCID: PMC10563805 DOI: 10.3389/bjbs.2023.11597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Accepted: 09/07/2023] [Indexed: 10/13/2023]
Abstract
Burkholderia cenocepacia is an opportunistic pathogen that is primarily associated with severe respiratory infections in people with cystic fibrosis. These bacteria have significant intrinsic resistance to antimicrobial therapy, and there is a need for more effective treatments. Bacterial zinc uptake and homeostasis systems are attractive targets for new drugs, yet our understanding of how bacteria acquire and utilise zinc remains incomplete. Here we have used RNA-sequencing and differential gene expression analysis to investigate how B. cenocepacia H111 is able to survive in zinc poor environments, such as those expected to be encountered within the host. The data shows that 201 genes are significantly differentially expressed when zinc supply is severely limited. Included in the 85 upregulated genes, are genes encoding a putative ZnuABC high affinity zinc importer, two TonB-dependent outer membrane receptors that may facilitate zinc uptake across the outer cell membrane, and a COG0523 family zinc metallochaperone. Amongst the 116 downregulated genes, are several zinc-dependent enzymes suggesting a mechanism of zinc sparring to reduce the cells demand for zinc when bioavailability is low.
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Affiliation(s)
- James Paul Barnett
- College of Life Sciences, Birmingham City University, Birmingham, United Kingdom
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4
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Huynh U, Nguyen HN, Trinh BK, Elhaj J, Zastrow ML. A bioinformatic analysis of zinc transporters in intestinal Lactobacillaceae. Metallomics 2023; 15:mfad044. [PMID: 37463796 PMCID: PMC10391621 DOI: 10.1093/mtomcs/mfad044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 07/17/2023] [Indexed: 07/20/2023]
Abstract
As the second most abundant transition element and a crucial cofactor for many proteins, zinc is essential for the survival of all living organisms. To maintain required zinc levels and prevent toxic overload, cells and organisms have a collection of metal transport proteins for uptake and efflux of zinc. In bacteria, metal transport proteins are well defined for model organisms and many pathogens, but fewer studies have explored metal transport proteins, including those for zinc, in commensal bacteria from the gut microbiota. The healthy human gut microbiota comprises hundreds of species and among these, bacteria from the Lactobacillaceae family are well documented to have various beneficial effects on health. Furthermore, changes in dietary metal intake, such as for zinc and iron, are frequently correlated with changes in abundance of Lactobacillaceae. Few studies have explored zinc requirements and zinc homeostasis mechanisms in Lactobacillaceae, however. Here we applied a bioinformatics approach to identify and compare predicted zinc uptake and efflux proteins in several Lactobacillaceae genera of intestinal relevance. Few Lactobacillaceae had zinc transporters currently annotated in proteomes retrieved from the UniProt database, but protein sequence-based homology searches revealed that high-affinity ABC transporter genes are likely common, albeit with genus-specific domain features. P-type ATPase transporters are probably also common and some Lactobacillaceae genera code for predicted zinc efflux cation diffusion facilitators. This analysis confirms that Lactobacillaceae harbor genes for various zinc transporter homologs, and provides a foundation for systematic experimental studies to elucidate zinc homeostasis mechanisms in these bacteria.
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Affiliation(s)
- Uyen Huynh
- Department of Chemistry, University of Houston, Houston, TX 77204, USA
| | - Hazel N Nguyen
- Department of Chemistry, University of Houston, Houston, TX 77204, USA
| | - Brittany K Trinh
- Department of Chemistry, University of Houston, Houston, TX 77204, USA
| | - Joanna Elhaj
- Department of Chemistry, University of Houston, Houston, TX 77204, USA
| | - Melissa L Zastrow
- Department of Chemistry, University of Houston, Houston, TX 77204, USA
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5
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McNutt ZA, Roy B, Gemler BT, Shatoff EA, Moon KM, Foster LJ, Bundschuh R, Fredrick K. Ribosomes lacking bS21 gain function to regulate protein synthesis in Flavobacterium johnsoniae. Nucleic Acids Res 2023; 51:1927-1942. [PMID: 36727479 PMCID: PMC9976891 DOI: 10.1093/nar/gkad047] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 01/12/2023] [Accepted: 01/16/2023] [Indexed: 02/03/2023] Open
Abstract
Ribosomes of Bacteroidia (formerly Bacteroidetes) fail to recognize Shine-Dalgarno (SD) sequences even though they harbor the anti-SD (ASD) of 16S rRNA. Inhibition of SD-ASD pairing is due to sequestration of the 3' tail of 16S rRNA in a pocket formed by bS21, bS18, and bS6 on the 30S platform. Interestingly, in many Flavobacteriales, the gene encoding bS21, rpsU, contains an extended SD sequence. In this work, we present genetic and biochemical evidence that bS21 synthesis in Flavobacterium johnsoniae is autoregulated via a subpopulation of ribosomes that specifically lack bS21. Mutation or depletion of bS21 in the cell increases translation of reporters with strong SD sequences, such as rpsU'-gfp, but has no effect on other reporters. Purified ribosomes lacking bS21 (or its C-terminal region) exhibit higher rates of initiation on rpsU mRNA and lower rates of initiation on other (SD-less) mRNAs than control ribosomes. The mechanism of autoregulation depends on extensive pairing between mRNA and 16S rRNA, and exceptionally strong SD sequences, with predicted pairing free energies of < -13 kcal/mol, are characteristic of rpsU across the Bacteroidota. This work uncovers a clear example of specialized ribosomes in bacteria.
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Affiliation(s)
- Zakkary A McNutt
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA.,Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Bappaditya Roy
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA.,Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA
| | - Bryan T Gemler
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA.,Interdisciplinary Biophysics Graduate Program, The Ohio State University, Columbus, OH 43210, USA
| | - Elan A Shatoff
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA.,Department of Physics, The Ohio State University, Columbus, OH 43210, USA
| | - Kyung-Mee Moon
- Department of Biochemistry and Molecular Biology, Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, V3T1Z4, Canada
| | - Leonard J Foster
- Department of Biochemistry and Molecular Biology, Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, V3T1Z4, Canada
| | - Ralf Bundschuh
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA.,Interdisciplinary Biophysics Graduate Program, The Ohio State University, Columbus, OH 43210, USA.,Department of Physics, The Ohio State University, Columbus, OH 43210, USA.,Department of Chemistry & Biochemistry, The Ohio State University, Columbus, OH 43210, USA.,Division of Hematology, Department of Internal Medicine, The Ohio State University, Columbus, OH 43210, USA
| | - Kurt Fredrick
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA.,Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA.,Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA
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6
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Wada A, Ueta M, Wada C. The Discovery of Ribosomal Protein bL31 from Escherichia coli: A Long Story Revisited. Int J Mol Sci 2023; 24:ijms24043445. [PMID: 36834855 PMCID: PMC9966373 DOI: 10.3390/ijms24043445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 02/04/2023] [Accepted: 02/06/2023] [Indexed: 02/11/2023] Open
Abstract
Ribosomal protein bL31 in Escherichia coli was initially detected as a short form (62 amino acids) using Kaltschmidt and Wittmann's two-dimensional polyacrylamide gel electrophoresis (2D PAGE), but the intact form (70 amino acids) was subsequently identified by means of Wada's improved radical-free and highly reducing (RFHR) 2D PAGE, which was consistent with the analysis of its encoding gene rpmE. Ribosomes routinely prepared from the K12 wild-type strain contained both forms of bL31. ΔompT cells, which lack protease 7, only contained intact bL31, suggesting that protease 7 cleaves intact bL31 and generates short bL31 during ribosome preparation from wild-type cells. Intact bL31 was required for subunit association, and its eight cleaved C-terminal amino acids contributed to this function. 70S ribosomes protected bL31 from cleavage by protease 7, but free 50S did not. In vitro translation was assayed using three systems. The translational activities of wild-type and ΔrpmE ribosomes were 20% and 40% lower than those of ΔompT ribosomes, which contained one copy of intact bL31. The deletion of bL31 reduces cell growth. A structural analysis predicted that bL31 spans the 30S and 50S subunits, consistent with its functions in 70S association and translation. It is important to re-analyze in vitro translation with ribosomes containing only intact bL31.
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Abstract
Living systems are built from a small subset of the atomic elements, including the bulk macronutrients (C,H,N,O,P,S) and ions (Mg,K,Na,Ca) together with a small but variable set of trace elements (micronutrients). Here, we provide a global survey of how chemical elements contribute to life. We define five classes of elements: those that are (i) essential for all life, (ii) essential for many organisms in all three domains of life, (iii) essential or beneficial for many organisms in at least one domain, (iv) beneficial to at least some species, and (v) of no known beneficial use. The ability of cells to sustain life when individual elements are absent or limiting relies on complex physiological and evolutionary mechanisms (elemental economy). This survey of elemental use across the tree of life is encapsulated in a web-based, interactive periodic table that summarizes the roles chemical elements in biology and highlights corresponding mechanisms of elemental economy.
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Affiliation(s)
- Kaleigh A Remick
- Department of Microbiology, Cornell University, New York, NY, United States
| | - John D Helmann
- Department of Microbiology, Cornell University, New York, NY, United States.
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8
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Rasmussen RA, Wang S, Camarillo JM, Sosnowski V, Cho BK, Goo Y, Lucks J, O’Halloran T. Zur and zinc increase expression of E. coli ribosomal protein L31 through RNA-mediated repression of the repressor L31p. Nucleic Acids Res 2022; 50:12739-12753. [PMID: 36533433 PMCID: PMC9825181 DOI: 10.1093/nar/gkac1086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 10/11/2022] [Accepted: 12/12/2022] [Indexed: 12/23/2022] Open
Abstract
Bacteria can adapt in response to numerous stress conditions. One such stress condition is zinc depletion. The zinc-sensing transcription factor Zur regulates the way numerous bacterial species respond to severe changes in zinc availability. Under zinc sufficient conditions, Zn-loaded Zur (Zn2-Zur) is well-known to repress transcription of genes encoding zinc uptake transporters and paralogues of a few ribosomal proteins. Here, we report the discovery and mechanistic basis for the ability of Zur to up-regulate expression of the ribosomal protein L31 in response to zinc in E. coli. Through genetic mutations and reporter gene assays, we find that Zur achieves the up-regulation of L31 through a double repression cascade by which Zur first represses the transcription of L31p, a zinc-lacking paralogue of L31, which in turn represses the translation of L31. Mutational analyses show that translational repression by L31p requires an RNA hairpin structure within the l31 mRNA and involves the N-terminus of the L31p protein. This work uncovers a new genetic network that allows bacteria to respond to host-induced nutrient limiting conditions through a sophisticated ribosomal protein switching mechanism.
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Affiliation(s)
- Rebecca A Rasmussen
- Interdisciplinary Biological Sciences Graduate Program, Northwestern University, Evanston, IL 60208, USA
- Chemistry of Life Process Institute, Northwestern University, Evanston, IL 60208, USA
| | - Suning Wang
- Chemistry of Life Process Institute, Northwestern University, Evanston, IL 60208, USA
- Department of Chemistry, Northwestern University, Evanston, IL 60208, USA
| | - Jeannie M Camarillo
- Northwestern Proteomics Core, Northwestern University, Evanston, IL 60208, USA
| | - Victoria Sosnowski
- Northwestern Proteomics Core, Northwestern University, Evanston, IL 60208, USA
| | - Byoung-Kyu Cho
- Northwestern Proteomics Core, Northwestern University, Evanston, IL 60208, USA
- Mass Spectrometry Technology Access Center, Washington University in St Louis, School of Medicine, USA
| | - Young Ah Goo
- Northwestern Proteomics Core, Northwestern University, Evanston, IL 60208, USA
- Mass Spectrometry Technology Access Center, Washington University in St Louis, School of Medicine, USA
| | - Julius B Lucks
- Interdisciplinary Biological Sciences Graduate Program, Northwestern University, Evanston, IL 60208, USA
- Chemistry of Life Process Institute, Northwestern University, Evanston, IL 60208, USA
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, IL 60208, USA
- Center for Synthetic Biology, Northwestern University, Evanston, IL 60208, USA
| | - Thomas V O’Halloran
- Chemistry of Life Process Institute, Northwestern University, Evanston, IL 60208, USA
- Department of Chemistry, Northwestern University, Evanston, IL 60208, USA
- Department of Chemistry, Michigan State University, East Lansing, MI 48824, USA
- Department of Microbiology & Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA
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9
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Murdoch CC, Skaar EP. Nutritional immunity: the battle for nutrient metals at the host-pathogen interface. Nat Rev Microbiol 2022; 20:657-670. [PMID: 35641670 PMCID: PMC9153222 DOI: 10.1038/s41579-022-00745-6] [Citation(s) in RCA: 143] [Impact Index Per Article: 71.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/04/2022] [Indexed: 12/21/2022]
Abstract
Trace metals are essential micronutrients required for survival across all kingdoms of life. From bacteria to animals, metals have critical roles as both structural and catalytic cofactors for an estimated third of the proteome, representing a major contributor to the maintenance of cellular homeostasis. The reactivity of metal ions engenders them with the ability to promote enzyme catalysis and stabilize reaction intermediates. However, these properties render metals toxic at high concentrations and, therefore, metal levels must be tightly regulated. Having evolved in close association with bacteria, vertebrate hosts have developed numerous strategies of metal limitation and intoxication that prevent bacterial proliferation, a process termed nutritional immunity. In turn, bacterial pathogens have evolved adaptive mechanisms to survive in conditions of metal depletion or excess. In this Review, we discuss mechanisms by which nutrient metals shape the interactions between bacterial pathogens and animal hosts. We explore the cell-specific and tissue-specific roles of distinct trace metals in shaping bacterial infections, as well as implications for future research and new therapeutic development.
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Affiliation(s)
- Caitlin C Murdoch
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN, USA
- Vanderbilt Institute for Infection, Immunology and Inflammation, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Eric P Skaar
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN, USA.
- Vanderbilt Institute for Infection, Immunology and Inflammation, Vanderbilt University School of Medicine, Nashville, TN, USA.
- Vanderbilt Institute for Chemical Biology, Vanderbilt University, Nashville, TN, USA.
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10
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Huynh U, Qiao M, King J, Trinh B, Valdez J, Haq M, Zastrow ML. Differential Effects of Transition Metals on Growth and Metal Uptake for Two Distinct Lactobacillus Species. Microbiol Spectr 2022; 10:e0100621. [PMID: 35080431 PMCID: PMC8791193 DOI: 10.1128/spectrum.01006-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Accepted: 12/23/2021] [Indexed: 12/12/2022] Open
Abstract
Lactobacillus is a genus of Gram-positive bacteria and comprises a major part of the lactic acid bacteria group that converts sugars to lactic acid. Lactobacillus species found in the gut microbiota are considered beneficial to human health and commonly used in probiotic formulations, but their molecular functions remain poorly defined. Microbes require metal ions for growth and function and must acquire them from the surrounding environment. Therefore, lactobacilli need to compete with other gut microbes for these nutrients, although their metal requirements are not well-understood. Indeed, the abundance of lactobacilli in the microbiota is frequently affected by dietary intake of essential metals like zinc, manganese, and iron, but few studies have investigated the role of metals, especially zinc, in the physiology and metabolism of Lactobacillus species. Here, we investigated metal uptake by quantifying total cellular metal contents and compared how transition metals affect the growth of two distinct Lactobacillus species, Lactobacillus plantarum ATCC 14917 and Lactobacillus acidophilus ATCC 4356. When grown in rich or metal-limited medium, both species took up more manganese, zinc, and iron compared with other transition metals measured. Distinct zinc-, manganese- and iron-dependent patterns were observed in the growth kinetics for these species and while certain levels of each metal promoted the growth kinetics of both Lactobacillus species, the effects depend significantly on the culture medium and growth conditions. IMPORTANCE The gastrointestinal tract contains trillions of microorganisms, which are central to human health. Lactobacilli are considered beneficial microbiota members and are often used in probiotics, but their molecular functions, and especially those which are metal-dependent, remain poorly defined. Abundance of lactobacilli in the microbiota is frequently affected by dietary intake of essential metals like manganese, zinc, and iron, but results are complex, sometimes contradictory, and poorly predictable. There is a significant need to understand how host diet and metabolism will affect the microbiota, given that changes in microbiota composition are linked with disease and infection. The significance of our research is in gaining insight to how metals distinctly affect individual Lactobacillus species, which could lead to novel therapeutics and improved medical treatment. Growth kinetics and quantification of metal contents highlights how distinct species can respond differently to varied metal availability and provide a foundation for future molecular and mechanistic studies.
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Affiliation(s)
- Uyen Huynh
- Department of Chemistry, University of Houston, Houston, Texas, United States
| | - Muxin Qiao
- Department of Chemistry, University of Houston, Houston, Texas, United States
| | - John King
- Department of Chemistry, University of Houston, Houston, Texas, United States
| | - Brittany Trinh
- Department of Chemistry, University of Houston, Houston, Texas, United States
| | - Juventino Valdez
- Department of Chemistry, University of Houston, Houston, Texas, United States
| | - Marium Haq
- Department of Chemistry, University of Houston, Houston, Texas, United States
| | - Melissa L. Zastrow
- Department of Chemistry, University of Houston, Houston, Texas, United States
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11
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Insights into the antibacterial mechanism of action of chelating agents by selective deprivation of iron, manganese and zinc. Appl Environ Microbiol 2021; 88:e0164121. [PMID: 34788072 PMCID: PMC8788741 DOI: 10.1128/aem.01641-21] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacterial growth and proliferation can be restricted by limiting the availability of metal ions in their environment. Humans sequester iron, manganese, and zinc to help prevent infection by pathogens, a system termed nutritional immunity. Commercially used chelants have high binding affinities with a variety of metal ions, which may lead to antibacterial properties that mimic these innate immune processes. However, the modes of action of many of these chelating agents in bacterial growth inhibition and their selectivity in metal deprivation in cellulo remain ill-defined. We address this shortcoming by examining the effect of 11 chelators on Escherichia coli growth and their impact on the cellular concentration of five metals. The following four distinct effects were uncovered: (i) no apparent alteration in metal composition, (ii) depletion of manganese alongside reductions in iron and zinc levels, (iii) reduced zinc levels with a modest reduction in manganese, and (iv) reduced iron levels coupled with elevated manganese. These effects do not correlate with the absolute known chelant metal ion affinities in solution; however, for at least five chelators for which key data are available, they can be explained by differences in the relative affinity of chelants for each metal ion. The results reveal significant insights into the mechanism of growth inhibition by chelants, highlighting their potential as antibacterials and as tools to probe how bacteria tolerate selective metal deprivation. IMPORTANCE Chelating agents are widely used in industry and consumer goods to control metal availability, with bacterial growth restriction as a secondary benefit for preservation. However, the antibacterial mechanism of action of chelants is largely unknown, particularly with respect to the impact on cellular metal concentrations. The work presented here uncovers distinct metal starvation effects imposed by different chelants on the model Gram-negative bacterium Escherichia coli. The chelators were studied both individually and in pairs, with the majority producing synergistic effects in combinations that maximize antibacterial hostility. The judicious selection of chelants based on contrasting cellular effects should enable reductions in the quantities of chelant required in numerous commercial products and presents opportunities to replace problematic chemistries with biodegradable alternatives.
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12
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Saldarriaga-Córdoba M, Irgang R, Avendaño-Herrera R. Comparison between genome sequences of Chilean Tenacibaculum dicentrarchi isolated from red conger eel (Genypterus chilensis) and Atlantic salmon (Salmo salar) focusing on bacterial virulence determinants. JOURNAL OF FISH DISEASES 2021; 44:1843-1860. [PMID: 34369594 DOI: 10.1111/jfd.13503] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 07/20/2021] [Accepted: 07/23/2021] [Indexed: 06/13/2023]
Abstract
Tenacibaculum dicentrarchi is an emerging pathogen for salmonid cultures and red conger eel (Genypterus chilensis) in Chile, causing high economic losses not only in Chile but also to the global salmon industry. Infected fish show severe gross skin lesions that are sometimes accompanied by bone exposure. Despite pathogenicity demonstrated by Koch's postulates, no knowledge is currently available regarding the virulence machinery of T. dicentrarchi strains. Comparisons between the genome sequences of the eight T. dicentrarchi strains obtained from G. chilensis and Atlantic salmon (Salmo salar) provide insights on the existence of genomic diversity within this bacterium. The T. dicentrarchi type strain 3509T was used as a reference genome. Depending on the T. dicentrarchi strain, the discovered diversity included genes associated with iron acquisition mechanisms, copper homeostasis encoding, resistance to tetracycline and fluoroquinolones, pathogenic genomic islands and phages. Interestingly, genes encoding the T9SS membrane protein PorP/SprF were retrieved in all of the analysed T. dicentrarchi strains, regardless of the host fish (i.e. red conger eel or Atlantic salmon). However, the T6SS core component protein VgrG was identified in only one Atlantic salmon strain. Three types of peptidase genes and proteins associated with quorum sensing were detected in all of the T. dicentrarchi strains. In turn, all eight strains presented a total of 17 proteins associated with biofilm formation, which was previously confirmed through physiological studies. This comparative analysis will help elucidate and describe the genes and pathways that are likely involved in the virulence process of T. dicentrarchi. All or part of these predicted genes could aid the pathogen during the infective process in fish, making further physiological research necessary for clarification.
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Affiliation(s)
- Mónica Saldarriaga-Córdoba
- Centro de Investigación en Recursos Naturales y Sustentabilidad, Universidad Bernardo O'Higgins, Santiago, Chile
| | - Rute Irgang
- Laboratorio de Patología de Organismos Acuáticos y Biotecnología Acuícola, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Viña del Mar, Chile
- Centro FONDAP, Interdisciplinary Center for Aquaculture Research (INCAR), Universidad Andrés Bello, Viña del Mar, Chile
| | - Ruben Avendaño-Herrera
- Laboratorio de Patología de Organismos Acuáticos y Biotecnología Acuícola, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Viña del Mar, Chile
- Centro FONDAP, Interdisciplinary Center for Aquaculture Research (INCAR), Universidad Andrés Bello, Viña del Mar, Chile
- Centro de Investigación Marina Quintay (CIMARQ), Universidad Andrés Bello, Quintay, Chile
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13
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Wang S, Cheng J, Niu Y, Li P, Zhang X, Lin J. Strategies for Zinc Uptake in Pseudomonas aeruginosa at the Host-Pathogen Interface. Front Microbiol 2021; 12:741873. [PMID: 34566943 PMCID: PMC8456098 DOI: 10.3389/fmicb.2021.741873] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Accepted: 08/23/2021] [Indexed: 11/13/2022] Open
Abstract
As a structural, catalytic, and signaling component, zinc is necessary for the growth and development of plants, animals, and microorganisms. Zinc is also essential for the growth of pathogenic microorganisms and is involved in their metabolism as well as the regulation of various virulence factors. Additionally, zinc is necessary for infection and colonization of pathogenic microorganisms in the host. Upon infection in healthy organisms, the host sequesters zinc both intracellularly and extracellularly to enhance the immune response and prevent the proliferation and infection of the pathogen. Intracellularly, the host manipulates zinc levels through Zrt/Irt-like protein (ZIP)/ZnT family proteins and various zinc storage proteins. Extracellularly, members of the S100 protein family, such as calgranulin C, sequester zinc to inhibit microbial growth. In the face of these nutritional limitations, bacteria rely on an efficient zinc transport system to maintain zinc supplementation for proliferation and disruption of the host defense system to establish infection. Here, we summarize the strategies for zinc uptake in conditional pathogenic Pseudomonas aeruginosa, including known zinc uptake systems (ZnuABC, HmtA, and ZrmABCD) and the zinc uptake regulator (Zur). In addition, other potential zinc uptake pathways were analyzed. This review systematically summarizes the process of zinc uptake by P. aeruginosa to provide guidance for the development of new drug targets.
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Affiliation(s)
- Shuaitao Wang
- College of Life Sciences, Yan'an University, Yan'an, China
| | - Juanli Cheng
- College of Life Sciences, Yan'an University, Yan'an, China.,Shaanxi Key Laboratory of Chinese Jujube, Yan'an University, Yan'an, China
| | - Yanting Niu
- College of Life Sciences, Yan'an University, Yan'an, China
| | - Panxin Li
- College of Life Sciences, Yan'an University, Yan'an, China
| | - Xiangqian Zhang
- College of Life Sciences, Yan'an University, Yan'an, China.,Shaanxi Key Laboratory of Chinese Jujube, Yan'an University, Yan'an, China
| | - Jinshui Lin
- College of Life Sciences, Yan'an University, Yan'an, China.,Shaanxi Key Laboratory of Chinese Jujube, Yan'an University, Yan'an, China
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14
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Hebdon SD, Gerritsen AT, Chen YP, Marcano JG, Chou KJ. Genome-Wide Transcription Factor DNA Binding Sites and Gene Regulatory Networks in Clostridium thermocellum. Front Microbiol 2021; 12:695517. [PMID: 34566906 PMCID: PMC8457756 DOI: 10.3389/fmicb.2021.695517] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 07/27/2021] [Indexed: 12/02/2022] Open
Abstract
Clostridium thermocellum is a thermophilic bacterium recognized for its natural ability to effectively deconstruct cellulosic biomass. While there is a large body of studies on the genetic engineering of this bacterium and its physiology to-date, there is limited knowledge in the transcriptional regulation in this organism and thermophilic bacteria in general. The study herein is the first report of a large-scale application of DNA-affinity purification sequencing (DAP-seq) to transcription factors (TFs) from a bacterium. We applied DAP-seq to > 90 TFs in C. thermocellum and detected genome-wide binding sites for 11 of them. We then compiled and aligned DNA binding sequences from these TFs to deduce the primary DNA-binding sequence motifs for each TF. These binding motifs are further validated with electrophoretic mobility shift assay (EMSA) and are used to identify individual TFs’ regulatory targets in C. thermocellum. Our results led to the discovery of novel, uncharacterized TFs as well as homologues of previously studied TFs including RexA-, LexA-, and LacI-type TFs. We then used these data to reconstruct gene regulatory networks for the 11 TFs individually, which resulted in a global network encompassing the TFs with some interconnections. As gene regulation governs and constrains how bacteria behave, our findings shed light on the roles of TFs delineated by their regulons, and potentially provides a means to enable rational, advanced genetic engineering of C. thermocellum and other organisms alike toward a desired phenotype.
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Affiliation(s)
- Skyler D Hebdon
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, United States
| | - Alida T Gerritsen
- Computational Sciences Center, National Renewable Energy Laboratory, Golden, CO, United States
| | - Yi-Pei Chen
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, United States
| | - Joan G Marcano
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, United States
| | - Katherine J Chou
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, United States
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15
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Gay DM, Lund AH, Jansson MD. Translational control through ribosome heterogeneity and functional specialization. Trends Biochem Sci 2021; 47:66-81. [PMID: 34312084 DOI: 10.1016/j.tibs.2021.07.001] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 06/18/2021] [Accepted: 07/01/2021] [Indexed: 12/31/2022]
Abstract
The conceptual origins of ribosome specialization can be traced back to the earliest days of molecular biology. Yet, this field has only recently begun to gather momentum, with numerous studies identifying distinct heterogeneous ribosome populations across multiple species and model systems. It is proposed that some of these compositionally distinct ribosomes may be functionally specialized and able to regulate the translation of specific mRNAs. Identification and functional characterization of specialized ribosomes has the potential to elucidate a novel layer of gene expression control, at the level of translation, where the ribosome itself is a key regulatory player. In this review, we discuss different sources of ribosome heterogeneity, evidence for ribosome specialization, and also the future directions of this exciting field.
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Affiliation(s)
- David M Gay
- Biotech Research and Innovation Centre, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Anders H Lund
- Biotech Research and Innovation Centre, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark.
| | - Martin D Jansson
- Biotech Research and Innovation Centre, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark.
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16
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Cunrath O, Palmer JD. An overview of Salmonella enterica metal homeostasis pathways during infection. ACTA ACUST UNITED AC 2021; 2:uqab001. [PMID: 34250489 PMCID: PMC8264917 DOI: 10.1093/femsml/uqab001] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 03/19/2021] [Indexed: 12/14/2022]
Abstract
Nutritional immunity is a powerful strategy at the core of the battlefield between host survival and pathogen proliferation. A host can prevent pathogens from accessing biological metals such as Mg, Fe, Zn, Mn, Cu, Co or Ni, or actively intoxicate them with metal overload. While the importance of metal homeostasis for the enteric pathogen Salmonella enterica Typhimurium was demonstrated many decades ago, inconsistent results across various mouse models, diverse Salmonella genotypes, and differing infection routes challenge aspects of our understanding of this phenomenon. With expanding access to CRISPR-Cas9 for host genome manipulation, it is now pertinent to re-visit past results in the context of specific mouse models, identify gaps and incongruities in current knowledge landscape of Salmonella homeostasis, and recommend a straight path forward towards a more universal understanding of this historic host-microbe relationship.
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Affiliation(s)
- Olivier Cunrath
- Department of Zoology, University of Oxford, Zoology Research and Administration Building, 11a Mansfield Rd, Oxford, UK OX1 3SZ
| | - Jacob D Palmer
- Department of Zoology, University of Oxford, Zoology Research and Administration Building, 11a Mansfield Rd, Oxford, UK OX1 3SZ
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17
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Zur: Zinc-Sensing Transcriptional Regulator in a Diverse Set of Bacterial Species. Pathogens 2021; 10:pathogens10030344. [PMID: 33804265 PMCID: PMC8000910 DOI: 10.3390/pathogens10030344] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 03/02/2021] [Accepted: 03/07/2021] [Indexed: 12/18/2022] Open
Abstract
Zinc (Zn) is the quintessential d block metal, needed for survival in all living organisms. While Zn is an essential element, its excess is deleterious, therefore, maintenance of its intracellular concentrations is needed for survival. The living organisms, during the course of evolution, developed proteins that can track the limitation or excess of necessary metal ions, thus providing survival benefits under variable environmental conditions. Zinc uptake regulator (Zur) is a regulatory transcriptional factor of the FUR superfamily of proteins, abundant among the bacterial species and known for its intracellular Zn sensing ability. In this study, we highlight the roles played by Zur in maintaining the Zn levels in various bacterial species as well as the fact that in recent years Zur has emerged not only as a Zn homeostatic regulator but also as a protein involved directly or indirectly in virulence of some pathogens. This functional aspect of Zur could be exploited in the ventures for the identification of newer antimicrobial targets. Despite extensive research on Zur, the insights into its overall regulon and its moonlighting functions in various pathogens yet remain to be explored. Here in this review, we aim to summarise the disparate functional aspects of Zur proteins present in various bacterial species.
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18
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Xia P, Lian S, Wu Y, Yan L, Quan G, Zhu G. Zinc is an important inter-kingdom signal between the host and microbe. Vet Res 2021; 52:39. [PMID: 33663613 PMCID: PMC7931793 DOI: 10.1186/s13567-021-00913-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2020] [Accepted: 02/08/2021] [Indexed: 12/15/2022] Open
Abstract
Zinc (Zn) is an essential trace element in living organisms and plays a vital role in the regulation of both microbial virulence and host immune responses. A growing number of studies have shown that zinc deficiency or the internal Zn concentration does not meet the needs of animals and microbes, leading to an imbalance in zinc homeostasis and intracellular signalling pathway dysregulation. Competition for zinc ions (Zn2+) between microbes and the host exists in the use of Zn2+ to maintain cell structure and physiological functions. It also affects the interplay between microbial virulence factors and their specific receptors in the host. This review will focus on the role of Zn in the crosstalk between the host and microbe, especially for changes in microbial pathogenesis and nociceptive neuron-immune interactions, as it may lead to new ways to prevent or treat microbial infections.
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Affiliation(s)
- Pengpeng Xia
- College of Veterinary Medicine (Institute of Comparative Medicine), Yangzhou University, Yangzhou, 225009, China. .,Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, 225009, China. .,Joint International Research Laboratory of Agriculture and Agri-Product Safety of Ministry of Education of China, Yangzhou University, Yangzhou, 225009, China.
| | - Siqi Lian
- College of Veterinary Medicine (Institute of Comparative Medicine), Yangzhou University, Yangzhou, 225009, China.,Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, 225009, China.,Joint International Research Laboratory of Agriculture and Agri-Product Safety of Ministry of Education of China, Yangzhou University, Yangzhou, 225009, China
| | - Yunping Wu
- College of Veterinary Medicine (Institute of Comparative Medicine), Yangzhou University, Yangzhou, 225009, China.,Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, 225009, China.,Joint International Research Laboratory of Agriculture and Agri-Product Safety of Ministry of Education of China, Yangzhou University, Yangzhou, 225009, China
| | - Li Yan
- College of Veterinary Medicine (Institute of Comparative Medicine), Yangzhou University, Yangzhou, 225009, China.,Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, 225009, China.,Joint International Research Laboratory of Agriculture and Agri-Product Safety of Ministry of Education of China, Yangzhou University, Yangzhou, 225009, China
| | - Guomei Quan
- College of Veterinary Medicine (Institute of Comparative Medicine), Yangzhou University, Yangzhou, 225009, China.,Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, 225009, China.,Joint International Research Laboratory of Agriculture and Agri-Product Safety of Ministry of Education of China, Yangzhou University, Yangzhou, 225009, China
| | - Guoqiang Zhu
- College of Veterinary Medicine (Institute of Comparative Medicine), Yangzhou University, Yangzhou, 225009, China. .,Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, 225009, China. .,Joint International Research Laboratory of Agriculture and Agri-Product Safety of Ministry of Education of China, Yangzhou University, Yangzhou, 225009, China.
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19
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Sukumaran A, Pladwig S, Geddes-McAlister J. Zinc limitation in Klebsiella pneumoniae profiled by quantitative proteomics influences transcriptional regulation and cation transporter-associated capsule production. BMC Microbiol 2021; 21:43. [PMID: 33568055 PMCID: PMC7874612 DOI: 10.1186/s12866-021-02091-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 01/12/2021] [Indexed: 01/02/2023] Open
Abstract
Background Microbial organisms encounter a variety of environmental conditions, including changes to metal ion availability. Metal ions play an important role in many biological processes for growth and survival. As such, microbes alter their cellular protein levels and secretion patterns in adaptation to a changing environment. This study focuses on Klebsiella pneumoniae, an opportunistic bacterium responsible for nosocomial infections. By using K. pneumoniae, we aim to determine how a nutrient-limited environment (e.g., zinc depletion) modulates the cellular proteome and secretome of the bacterium. By testing virulence in vitro, we provide novel insight into bacterial responses to limited environments in the presence of the host. Results Analysis of intra- and extracellular changes identified 2380 proteins from the total cellular proteome (cell pellet) and 246 secreted proteins (supernatant). Specifically, HutC, a repressor of the histidine utilization operon, showed significantly increased abundance under zinc-replete conditions, which coincided with an expected reduction in expression of genes within the hut operon from our validating qRT-PCR analysis. Additionally, we characterized a putative cation transport regulator, ChaB that showed significantly higher abundance under zinc-replete vs. -limited conditions, suggesting a role in metal ion homeostasis. Phenotypic analysis of a chaB deletion strain demonstrated a reduction in capsule production, zinc-dependent growth and ion utilization, and reduced virulence when compared to the wild-type strain. Conclusions This is first study to comprehensively profile the impact of zinc availability on the proteome and secretome of K. pneumoniae and uncover a novel connection between zinc transport and capsule production in the bacterial system. Supplementary Information The online version contains supplementary material available at 10.1186/s12866-021-02091-8.
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Affiliation(s)
- A Sukumaran
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, N1G 2W1, Canada
| | - S Pladwig
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, N1G 2W1, Canada
| | - J Geddes-McAlister
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, N1G 2W1, Canada.
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20
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Sevilla E, Bes MT, Peleato ML, Fillat MF. Fur-like proteins: Beyond the ferric uptake regulator (Fur) paralog. Arch Biochem Biophys 2021; 701:108770. [PMID: 33524404 DOI: 10.1016/j.abb.2021.108770] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 01/12/2021] [Accepted: 01/17/2021] [Indexed: 10/22/2022]
Abstract
Proteins belonging to the FUR (ferric uptake regulator) family are the cornerstone of metalloregulation in most prokaryotes. Although numerous reviews have been devoted to these proteins, these reports are mainly focused on the Fur paralog that gives name to the family. In the last years, the increasing knowledge on the other, less ubiquitous members of this family has evidenced their importance in bacterial metabolism. As the Fur paralog, the major regulator of iron homeostasis, Zur, Irr, BosR and PerR are tightly related to stress defenses and host-pathogen interaction being in many cases essential for virulence. Furthermore, the Nur and Mur paralogs largely contribute to control nickel and manganese homeostasis, which are cofactors of pivotal proteins for host colonization and bacterial redox homeostasis. The present review highlights the main features of FUR proteins that differ to the canonical Fur paralog either in the coregulatory metal, such as Zur, Nur and Mur, or in the action mechanism to control target genes, such as PerR, Irr and BosR.
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Affiliation(s)
- Emma Sevilla
- Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Instituto de Biocomputación y Física de Sistemas Complejos (GBsC-CSIC and BIFI-IQFR Joint Units), Universidad de Zaragoza, Zaragoza, Spain
| | - M Teresa Bes
- Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Instituto de Biocomputación y Física de Sistemas Complejos (GBsC-CSIC and BIFI-IQFR Joint Units), Universidad de Zaragoza, Zaragoza, Spain
| | - M Luisa Peleato
- Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Instituto de Biocomputación y Física de Sistemas Complejos (GBsC-CSIC and BIFI-IQFR Joint Units), Universidad de Zaragoza, Zaragoza, Spain
| | - María F Fillat
- Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Instituto de Biocomputación y Física de Sistemas Complejos (GBsC-CSIC and BIFI-IQFR Joint Units), Universidad de Zaragoza, Zaragoza, Spain.
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21
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Molecular Mechanisms of Phosphate Sensing, Transport and Signalling in Streptomyces and Related Actinobacteria. Int J Mol Sci 2021; 22:ijms22031129. [PMID: 33498785 PMCID: PMC7866108 DOI: 10.3390/ijms22031129] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2021] [Revised: 01/18/2021] [Accepted: 01/20/2021] [Indexed: 12/13/2022] Open
Abstract
Phosphorous, in the form of phosphate, is a key element in the nutrition of all living beings. In nature, it is present in the form of phosphate salts, organophosphates, and phosphonates. Bacteria transport inorganic phosphate by the high affinity phosphate transport system PstSCAB, and the low affinity PitH transporters. The PstSCAB system consists of four components. PstS is the phosphate binding protein and discriminates between arsenate and phosphate. In the Streptomyces species, the PstS protein, attached to the outer side of the cell membrane, is glycosylated and released as a soluble protein that lacks its phosphate binding ability. Transport of phosphate by the PstSCAB system is drastically regulated by the inorganic phosphate concentration and mediated by binding of phosphorylated PhoP to the promoter of the PstSCAB operon. In Mycobacterium smegmatis, an additional high affinity transport system, PhnCDE, is also under PhoP regulation. Additionally, Streptomyces have a duplicated low affinity phosphate transport system encoded by the pitH1–pitH2 genes. In this system phosphate is transported as a metal-phosphate complex in simport with protons. Expression of pitH2, but not that of pitH1 in Streptomyces coelicolor, is regulated by PhoP. Interestingly, in many Streptomyces species, three gene clusters pitH1–pstSCAB–ppk (for a polyphosphate kinase), are linked in a supercluster formed by nine genes related to phosphate metabolism. Glycerol-3-phosphate may be transported by the actinobacteria Corynebacterium glutamicum that contains a ugp gene cluster for glycerol-3-P uptake, but the ugp cluster is not present in Streptomyces genomes. Sugar phosphates and nucleotides are used as phosphate source by the Streptomyces species, but there is no evidence of the uhp gene involved in the transport of sugar phosphates. Sugar phosphates and nucleotides are dephosphorylated by extracellular phosphatases and nucleotidases. An isolated uhpT gene for a hexose phosphate antiporter is present in several pathogenic corynebacteria, such as Corynebacterium diphtheriae, but not in non-pathogenic ones. Phosphonates are molecules that contains phosphate linked covalently to a carbon atom through a very stable C–P bond. Their utilization requires the phnCDE genes for phosphonates/phosphate transport and genes for degradation, including those for the subunits of the C–P lyase. Strains of the Arthrobacter and Streptomyces genera were reported to degrade simple phosphonates, but bioinformatic analysis reveals that whole sets of genes for putative phosphonate degradation are present only in three Arthrobacter species and a few Streptomyces species. Genes encoding the C–P lyase subunits occur in several Streptomyces species associated with plant roots or with mangroves, but not in the laboratory model Streptomyces species; however, the phnCDE genes that encode phosphonates/phosphate transport systems are frequent in Streptomyces species, suggesting that these genes, in the absence of C–P lyase genes, might be used as surrogate phosphate transporters. In summary, Streptomyces and related actinobacteria seem to be less versatile in phosphate transport systems than Enterobacteria.
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22
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Zhang L, Bill E, Kroneck PMH, Einsle O. A [3Cu:2S] cluster provides insight into the assembly and function of the Cu Z site of nitrous oxide reductase. Chem Sci 2021; 12:3239-3244. [PMID: 34164092 PMCID: PMC8179356 DOI: 10.1039/d0sc05204c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Nitrous oxide reductase (N2OR) is the only known enzyme reducing environmentally critical nitrous oxide (N2O) to dinitrogen (N2) as the final step of bacterial denitrification. The assembly process of its unique catalytic [4Cu:2S] cluster CuZ remains scarcely understood. Here we report on a mutagenesis study of all seven histidine ligands coordinating this copper center, followed by spectroscopic and structural characterization and based on an established, functional expression system for Pseudomonas stutzeri N2OR in Escherichia coli. While no copper ion was found in the CuZ binding site of variants H129A, H130A, H178A, H326A, H433A and H494A, the H382A variant carried a catalytically inactive [3Cu:2S] center, in which one sulfur ligand, SZ2, had relocated to form a weak hydrogen bond to the sidechain of the nearby lysine residue K454. This link provides sufficient stability to avoid the loss of the sulfide anion. The UV-vis spectra of this cluster are strikingly similar to those of the active enzyme, implying that the flexibility of SZ2 may have been observed before, but not recognized. The sulfide shift changes the metal coordination in CuZ and is thus of high mechanistic interest. Variants of all seven histidine ligands of the [4Cu:2S] active site of nitrous oxide reductase mostly result in loss of the metal site. However, a H382A variant retains a [3Cu:2S] cluster that hints towards a structural flexibility also present in the intact site.![]()
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Affiliation(s)
- Lin Zhang
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg Albertstrasse 21 79104 Freiburg im Breisgau Germany
| | - Eckhard Bill
- Max-Planck-Institut für Chemische Energiekonversion Stiftstr. 34-36 D-45470 Mülheim an der Ruhr Germany
| | | | - Oliver Einsle
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg Albertstrasse 21 79104 Freiburg im Breisgau Germany
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23
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Cheng-Guang H, Gualerzi CO. The Ribosome as a Switchboard for Bacterial Stress Response. Front Microbiol 2021; 11:619038. [PMID: 33584583 PMCID: PMC7873864 DOI: 10.3389/fmicb.2020.619038] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Accepted: 12/03/2020] [Indexed: 12/29/2022] Open
Abstract
As free-living organisms, bacteria are subject to continuous, numerous and occasionally drastic environmental changes to which they respond with various mechanisms which enable them to adapt to the new conditions so as to survive. Here we describe three situations in which the ribosome and its functions represent the sensor or the target of the stress and play a key role in the subsequent cellular response. The three stress conditions which are described are those ensuing upon: a) zinc starvation; b) nutritional deprivation, and c) temperature downshift.
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24
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Zhang L, Bill E, Kroneck PMH, Einsle O. Histidine-Gated Proton-Coupled Electron Transfer to the CuA Site of Nitrous Oxide Reductase. J Am Chem Soc 2020; 143:830-838. [DOI: 10.1021/jacs.0c10057] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Lin Zhang
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, Albertstraße 21, 79104 Freiburg im Breisgau, Germany
| | - Eckhard Bill
- Max-Planck-Institut für Chemische Energiekonversion, Stiftstraße 34-36, D-45470 Mülheim an der Ruhr, Germany
| | | | - Oliver Einsle
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, Albertstraße 21, 79104 Freiburg im Breisgau, Germany
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25
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Kharadi RR, Sundin GW. Cyclic-di-GMP Regulates Autoaggregation Through the Putative Peptidoglycan Hydrolase, EagA, and Regulates Transcription of the znuABC Zinc Uptake Gene Cluster in Erwinia amylovora. Front Microbiol 2020; 11:605265. [PMID: 33281804 PMCID: PMC7705223 DOI: 10.3389/fmicb.2020.605265] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 10/27/2020] [Indexed: 11/24/2022] Open
Abstract
Erwinia amylovora is the causal agent of fire blight, an economically impactful disease that affects apple and pear production worldwide. E. amylovora pathogenesis is comprised of distinct type III secretion-dependent and biofilm-dependent stages. Alterations in the intracellular levels of cyclic-di-GMP (c-di-GMP) regulate the transition between the different stages of infection in E. amylovora. We previously reported that hyper-elevation of c-di-GMP levels in E. amylovora Ea1189, resulting from the deletion of all three c-di-GMP specific phosphodiesterase genes (Ea1189ΔpdeABC), resulted in an autoaggregation phenotype. The two major exopolysaccharides, amylovoran and cellulose, were also shown to partially contribute to autoaggregation. In this study, we aimed to identify the c-di-GMP dependent factor(s) that contributes to autoaggregation. We conducted a transposon mutant screen in Ea1189ΔpdeABC and selected for loss of autoaggregation. Our search identified a peptidoglycan hydrolase, specifically, a D, D-endopeptidase of the metallopeptidase class, EagA (Erwiniaaggregation factor A), that was found to physiologically contribute to autoaggregation in a c-di-GMP dependent manner. The production of amylovoran was also positively affected by EagA levels. An eagA deletion mutant (Ea1189ΔeagA) was significantly reduced in virulence compared to the wild type E. amylovora Ea1189. eagA is part of the znuABC zinc uptake gene cluster and is located within an operon downstream of znuA. The znuAeagA/znuCB gene cluster was transcriptionally regulated by elevated levels of c-di-GMP as well as by the zinc-dependent transcriptional repressor Zur. We also observed that with an influx of Zn2+ in the environment, the transcription of the znuAeagA/znuBC gene cluster is regulated by both Zur and a yet to be characterized c-di-GMP dependent pathway.
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Affiliation(s)
- Roshni R Kharadi
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, MI, United States
| | - George W Sundin
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, MI, United States
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26
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Costello A, Parker J, Clynes M, Murphy R. Development of whole-cell and cell-free biosensors for the detection and differentiation of organic and inorganic forms of copper. Metallomics 2020; 12:1729-1734. [PMID: 33029604 DOI: 10.1039/d0mt00146e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The modern world has seen exposure of bacterial communities to toxic metals at selective levels. This manifests itself both intentionally, through medicines and un-intentionally through waste streams. There is growing concern that selective exposure to metals may be linked to microbial resistance to antibiotics. For a microbe to become resistant to a specific metal it must first come in contact with it. The transition metal copper has the ability to enter bacterial cells without need for a copper specific uptake mechanism. Copper is commonly used as an antimicrobial in the healthcare industry, consumer products and as a growth promoter of livestock in the agricultural sector. Here we report a study into the uptake of different organic and inorganic sources of copper. A whole-cell bacterial biosensor was developed to quantify the specific uptake of copper from various sources. Furthermore, a cell-free sensor was utilized to investigate the response to copper sources when uptake is eliminated as a factor. The data within suggest inorganic copper to have greatly reduced uptake compared to organic sources and that there is significant difference between copper oxides, Cu2O and CuO.
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Affiliation(s)
- Alan Costello
- National Institute for Cellular Biotechnology and SSPC-SFI Centre for Pharmaceuticals, Dublin City University, Dublin 9, Ireland.
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Galardini M, Clermont O, Baron A, Busby B, Dion S, Schubert S, Beltrao P, Denamur E. Major role of iron uptake systems in the intrinsic extra-intestinal virulence of the genus Escherichia revealed by a genome-wide association study. PLoS Genet 2020; 16:e1009065. [PMID: 33112851 PMCID: PMC7592755 DOI: 10.1371/journal.pgen.1009065] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 08/20/2020] [Indexed: 11/18/2022] Open
Abstract
The genus Escherichia is composed of several species and cryptic clades, including E. coli, which behaves as a vertebrate gut commensal, but also as an opportunistic pathogen involved in both diarrheic and extra-intestinal diseases. To characterize the genetic determinants of extra-intestinal virulence within the genus, we carried out an unbiased genome-wide association study (GWAS) on 370 commensal, pathogenic and environmental strains representative of the Escherichia genus phylogenetic diversity and including E. albertii (n = 7), E. fergusonii (n = 5), Escherichia clades (n = 32) and E. coli (n = 326), tested in a mouse model of sepsis. We found that the presence of the high-pathogenicity island (HPI), a ~35 kbp gene island encoding the yersiniabactin siderophore, is highly associated with death in mice, surpassing other associated genetic factors also related to iron uptake, such as the aerobactin and the sitABCD operons. We confirmed the association in vivo by deleting key genes of the HPI in E. coli strains in two phylogenetic backgrounds. We then searched for correlations between virulence, iron capture systems and in vitro growth in a subset of E. coli strains (N = 186) previously phenotyped across growth conditions, including antibiotics and other chemical and physical stressors. We found that virulence and iron capture systems are positively correlated with growth in the presence of numerous antibiotics, probably due to co-selection of virulence and resistance. We also found negative correlations between virulence, iron uptake systems and growth in the presence of specific antibiotics (i.e. cefsulodin and tobramycin), which hints at potential “collateral sensitivities” associated with intrinsic virulence. This study points to the major role of iron capture systems in the extra-intestinal virulence of the genus Escherichia. Bacterial isolates belonging to the genus Escherichia can be human commensals but also opportunistic pathogens, with the ability to cause extra-intestinal infection. There is therefore the need to identify the genetic elements that favour extra-intestinal virulence, so that virulent bacterial isolates can be identified through genome analysis and potential treatment strategies be developed. To reduce the influence of host variability on virulence, we have used a mouse model of sepsis to characterize the virulence of 370 strains belonging to the genus Escherichia, for which whole genome sequences were also available. We have used a statistical approach called Genome-Wide Association Study (GWAS) to show how the presence of genes that encode for iron scavenging are significantly associated with the propensity of a bacterial isolate to cause extra-intestinal infections. Taking advantage of previously generated growth data on a subset of the strains and its correlation to virulence we generated hypothesis on the relationship between iron scavenging and growth in the presence of various antimicrobials, which could have implications for developing new treatment strategies.
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Affiliation(s)
- Marco Galardini
- EMBL-EBI, Wellcome Genome Campus, Cambridge, United Kingdom
- * E-mail: (MG); (ED)
| | | | | | - Bede Busby
- Genome Biology Unit, EMBL, Heidelberg, Germany
| | - Sara Dion
- Université de Paris, IAME, UMR1137, INSERM, Paris, France
| | - Sören Schubert
- Max von Pettenkofer Institute of Hygiene and Medical Microbiology, Faculty of Medicine, LMU Munich, Germany
| | - Pedro Beltrao
- EMBL-EBI, Wellcome Genome Campus, Cambridge, United Kingdom
| | - Erick Denamur
- Université de Paris, IAME, UMR1137, INSERM, Paris, France
- AP-HP, Laboratoire de Génétique Moléculaire, Hôpital Bichat, Paris, France
- * E-mail: (MG); (ED)
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Ananth A, Han I, Akter M, Boo JH, Choi EH. Handy Soft Jet Plasma as an Effective Technique for Tailored Preparation of ZnS Nanomaterials and Shape Dependent Antibacterial Performance of ZnS. J IND ENG CHEM 2020. [DOI: 10.1016/j.jiec.2020.07.042] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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A steady-state model of microbial acclimation to substrate limitation. PLoS Comput Biol 2020; 16:e1008140. [PMID: 32845915 PMCID: PMC7478835 DOI: 10.1371/journal.pcbi.1008140] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 09/08/2020] [Accepted: 07/09/2020] [Indexed: 11/19/2022] Open
Abstract
Microbes acclimate to changes in substrate availability by altering the number of transporters on the cell surface, however there is some disagreement on just how. We revisit the physics of substrate uptake and consider the steady-state scenario whereby cells have acclimated to maximize fitness. Flux balance analysis of a stoichiometric model of Escherichia coli was used in conjunction with quantitative proteomics data and molecular modeling of membrane transporters to reconcile these opposing views. An emergent feature of the proposed model is a critical substrate concentration S*, which delineates two rate limits. At concentrations above S*, transporter abundance can be regulated to maintain uptake rates as demanded by maximal growth rates, whereas below S*, uptake rates are strictly diffusion limited. In certain scenarios, the proposed model can take on a qualitatively different shape from the familiar hyperbolic kinetics curves, instead resembling the long-forgotten Blackman kinetics.
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Meni A, Yukl ET. Structural Features Mediating Zinc Binding and Transfer in the AztABCD Zinc Transporter System. Biomolecules 2020; 10:biom10081156. [PMID: 32781785 PMCID: PMC7463823 DOI: 10.3390/biom10081156] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 08/03/2020] [Accepted: 08/04/2020] [Indexed: 12/27/2022] Open
Abstract
Many bacteria require ATP binding cassette (ABC) transporters for the import of the essential metal zinc from limited environments. These systems rely on a periplasmic or cell-surface solute binding protein (SBP) to bind zinc with high affinity and specificity. AztABCD is one such zinc transport system recently identified in a large group of diverse bacterial species. In addition to a classical SBP (AztC), the operon also includes a periplasmic metallochaperone (AztD) shown to transfer zinc directly to AztC. Crystal structures of both proteins from Paracoccus denitrificans have been solved and suggest several structural features on each that may be important for zinc binding and transfer. Here we determine zinc binding affinity, dissociation kinetics, and transfer kinetics for several deletion mutants as well as a crystal structure for one of them. The results indicate specific roles for loop structures on AztC and an N-terminal motif on AztD in zinc binding and transfer. These data are consistent with a structural transfer model proposed previously and provide further mechanistic insight into the processes of zinc binding and transfer.
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Ueta M, Wada C, Wada A. YkgM and YkgO maintain translation by replacing their paralogs, zinc‐binding ribosomal proteins L31 and L36, with identical activities. Genes Cells 2020; 25:562-581. [DOI: 10.1111/gtc.12796] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 05/08/2020] [Accepted: 05/22/2020] [Indexed: 12/18/2022]
Affiliation(s)
| | | | - Akira Wada
- Yoshida Biological Laboratory Kyoto Japan
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32
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Lilleorg S, Reier K, Volõnkin P, Remme J, Liiv A. Phenotypic effects of paralogous ribosomal proteins bL31A and bL31B in E. coli. Sci Rep 2020; 10:11682. [PMID: 32669635 PMCID: PMC7363858 DOI: 10.1038/s41598-020-68582-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2020] [Accepted: 06/24/2020] [Indexed: 02/07/2023] Open
Abstract
Ribosomes are essential macromolecular complexes conducting protein biosynthesis in all domains of life. Cells can have heterogeneous ribosomes, i.e. ribosomes with various ribosomal RNA and ribosomal protein (r-protein) composition. However, the functional importance of heterogeneous ribosomes has remained elusive. One of the possible sources for ribosome heterogeneity is provided by paralogous r-proteins. In E. coli, ribosomal protein bL31 has two paralogs: bL31A encoded by rpmE and bL31B encoded by ykgM. This study investigates phenotypic effects of these ribosomal protein paralogs using bacterial strains expressing only bL31A or bL31B. We show that bL31A confers higher fitness to E. coli under lower temperatures. In addition, bL31A and bL31B have different effects on translation reading frame maintenance and apparent translation processivity in vivo as demonstrated by dual luciferase assay. In general, this study demonstrates that ribosomal protein paralog composition (bL31A versus bL31B) can affect cell growth and translation outcome.
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Affiliation(s)
- Silva Lilleorg
- Institute of Molecular and Cell Biology, University of Tartu, Riia street 23B, 51010, Tartu, Estonia
| | - Kaspar Reier
- Institute of Molecular and Cell Biology, University of Tartu, Riia street 23B, 51010, Tartu, Estonia
| | - Pavel Volõnkin
- Institute of Molecular and Cell Biology, University of Tartu, Riia street 23B, 51010, Tartu, Estonia
| | - Jaanus Remme
- Institute of Molecular and Cell Biology, University of Tartu, Riia street 23B, 51010, Tartu, Estonia
| | - Aivar Liiv
- Institute of Molecular and Cell Biology, University of Tartu, Riia street 23B, 51010, Tartu, Estonia.
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Danchin A, Sekowska A, You C. One-carbon metabolism, folate, zinc and translation. Microb Biotechnol 2020; 13:899-925. [PMID: 32153134 PMCID: PMC7264889 DOI: 10.1111/1751-7915.13550] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Accepted: 02/17/2020] [Indexed: 12/16/2022] Open
Abstract
The translation process, central to life, is tightly connected to the one-carbon (1-C) metabolism via a plethora of macromolecule modifications and specific effectors. Using manual genome annotations and putting together a variety of experimental studies, we explore here the possible reasons of this critical interaction, likely to have originated during the earliest steps of the birth of the first cells. Methionine, S-adenosylmethionine and tetrahydrofolate dominate this interaction. Yet, 1-C metabolism is unlikely to be a simple frozen accident of primaeval conditions. Reactive 1-C species (ROCS) are buffered by the translation machinery in a way tightly associated with the metabolism of iron-sulfur clusters, zinc and potassium availability, possibly coupling carbon metabolism to nitrogen metabolism. In this process, the highly modified position 34 of tRNA molecules plays a critical role. Overall, this metabolic integration may serve both as a protection against the deleterious formation of excess carbon under various growth transitions or environmental unbalanced conditions and as a regulator of zinc homeostasis, while regulating input of prosthetic groups into nascent proteins. This knowledge should be taken into account in metabolic engineering.
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Affiliation(s)
- Antoine Danchin
- AMAbiotics SASInstitut Cochin24 rue du Faubourg Saint‐Jacques75014ParisFrance
- School of Biomedical SciencesLi Ka Shing Faculty of MedicineThe University of Hong KongS.A.R. Hong KongChina
| | - Agnieszka Sekowska
- AMAbiotics SASInstitut Cochin24 rue du Faubourg Saint‐Jacques75014ParisFrance
| | - Conghui You
- Shenzhen Key Laboratory of Microbial Genetic EngineeringCollege of Life Sciences and OceanologyShenzhen University1066 Xueyuan Rd518055ShenzhenChina
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34
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Jung W, Sengupta K, Wendel BM, Helmann JD, Chen P. Biphasic unbinding of a metalloregulator from DNA for transcription (de)repression in Live Bacteria. Nucleic Acids Res 2020; 48:2199-2208. [PMID: 32009151 PMCID: PMC7049717 DOI: 10.1093/nar/gkaa056] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 01/06/2020] [Accepted: 01/17/2020] [Indexed: 11/12/2022] Open
Abstract
Microorganisms use zinc-sensing regulators to alter gene expression in response to changes in the availability of zinc, an essential micronutrient. Under zinc-replete conditions, the Fur-family metalloregulator Zur binds to DNA tightly in its metallated repressor form to Zur box operator sites, repressing the transcription of zinc uptake transporters. Derepression comes from unbinding of the regulator, which, under zinc-starvation conditions, exists in its metal-deficient non-repressor forms having no significant affinity with Zur box. While the mechanism of transcription repression by Zur is well-studied, little is known on how derepression by Zur could be facilitated. Using single-molecule/single-cell measurements, we find that in live Escherichia coli cells, Zur's unbinding rate from DNA is sensitive to Zur protein concentration in a first-of-its-kind biphasic manner, initially impeded and then facilitated with increasing Zur concentration. These results challenge conventional models of protein unbinding being unimolecular processes and independent of protein concentration. The facilitated unbinding component likely occurs via a ternary complex formation mechanism. The impeded unbinding component likely results from Zur oligomerization on chromosome involving inter-protein salt-bridges. Unexpectedly, a non-repressor form of Zur is found to bind chromosome tightly, likely at non-consensus sequence sites. These unusual behaviors could provide functional advantages in Zur's facile switching between repression and derepression.
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Affiliation(s)
- Won Jung
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA
| | - Kushal Sengupta
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA
| | - Brian M Wendel
- Department of Microbiology, Cornell University, Ithaca, NY 14853, USA
| | - John D Helmann
- Department of Microbiology, Cornell University, Ithaca, NY 14853, USA
| | - Peng Chen
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA
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Metallochaperones Are Needed for Mycobacterium tuberculosis and Escherichia coli Nicotinamidase-Pyrazinamidase Activity. J Bacteriol 2020; 202:JB.00331-19. [PMID: 31636108 PMCID: PMC6941528 DOI: 10.1128/jb.00331-19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 10/04/2019] [Indexed: 11/20/2022] Open
Abstract
Tuberculosis is an infectious disease caused by the bacterium Mycobacterium tuberculosis and remains one of the major causes of disease and death worldwide. Pyrazinamide is a key drug used in the treatment of tuberculosis, yet its mechanism of action is not fully understood, and testing strains of M. tuberculosis for pyrazinamide resistance is not easy with the tools that are presently available. The significance of the present research is that a metallochaperone-like protein may be crucial to pyrazinamide’s mechanisms of action and of resistance. This may support the development of improved tools to detect pyrazinamide resistance, which would have significant implications for the clinical management of patients with tuberculosis: drug regimens that are appropriately tailored to the resistance profile of a patient’s individual strain lead to better clinical outcomes, reduced onward transmission of infection, and reduction of the development of resistant strains that are more challenging and expensive to treat. Mycobacterium tuberculosis nicotinamidase-pyrazinamidase (PZAse) is a metalloenzyme that catalyzes conversion of nicotinamide-pyrazinamide to nicotinic acid-pyrazinoic acid. This study investigated whether a metallochaperone is required for optimal PZAse activity. M. tuberculosis and Escherichia coli PZAses (PZAse-MT and PZAse-EC, respectively) were inactivated by metal depletion (giving PZAse-MT–Apo and PZAse-EC–Apo). Reactivation with the E. coli metallochaperone ZnuA or Rv2059 (the M. tuberculosis analog) was measured. This was repeated following proteolytic and thermal treatment of ZnuA and Rv2059. The CDC1551 M. tuberculosis reference strain had the Rv2059 coding gene knocked out, and PZA susceptibility and the pyrazinoic acid (POA) efflux rate were measured. ZnuA (200 μM) achieved 65% PZAse-EC–Apo reactivation. Rv2059 (1 μM) and ZnuA (1 μM) achieved 69% and 34.3% PZAse-MT–Apo reactivation, respectively. Proteolytic treatment of ZnuA and Rv2059 and application of three (but not one) thermal shocks to ZnuA significantly reduced the capacity to reactivate PZAse-MT–Apo. An M. tuberculosis Rv2059 knockout strain was Wayne positive and susceptible to PZA and did not have a significantly different POA efflux rate than the reference strain, although a trend toward a lower efflux rate was observed after knockout. The metallochaperone Rv2059 restored the activity of metal-depleted PZAse in vitro. Although Rv2059 is important in vitro, it seems to have a smaller effect on PZA susceptibility in vivo. It may be important to mechanisms of action and resistance to pyrazinamide in M. tuberculosis. Further studies are needed for confirmation. IMPORTANCE Tuberculosis is an infectious disease caused by the bacterium Mycobacterium tuberculosis and remains one of the major causes of disease and death worldwide. Pyrazinamide is a key drug used in the treatment of tuberculosis, yet its mechanism of action is not fully understood, and testing strains of M. tuberculosis for pyrazinamide resistance is not easy with the tools that are presently available. The significance of the present research is that a metallochaperone-like protein may be crucial to pyrazinamide’s mechanisms of action and of resistance. This may support the development of improved tools to detect pyrazinamide resistance, which would have significant implications for the clinical management of patients with tuberculosis: drug regimens that are appropriately tailored to the resistance profile of a patient’s individual strain lead to better clinical outcomes, reduced onward transmission of infection, and reduction of the development of resistant strains that are more challenging and expensive to treat.
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Johanns VC, Ghazisaeedi F, Epping L, Semmler T, Lübke-Becker A, Pfeifer Y, Bethe A, Eichhorn I, Merle R, Walther B, Wieler LH. Effects of a Four-Week High-Dosage Zinc Oxide Supplemented Diet on Commensal Escherichia coli of Weaned Pigs. Front Microbiol 2019; 10:2734. [PMID: 31849886 PMCID: PMC6892955 DOI: 10.3389/fmicb.2019.02734] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Accepted: 11/11/2019] [Indexed: 12/11/2022] Open
Abstract
Strategies to reduce economic losses associated with post-weaning diarrhea in pig farming include high-level dietary zinc oxide supplementation. However, excessive usage of zinc oxide in the pig production sector was found to be associated with accumulation of multidrug resistant bacteria in these animals, presenting an environmental burden through contaminated manure. Here we report on zinc tolerance among a random selection of intestinal Escherichia coli comprising of different antibiotic resistance phenotypes and sampling sites isolated during a controlled feeding trial from 16 weaned piglets: In total, 179 isolates from "pigs fed with high zinc concentrations" (high zinc group, [HZG]: n = 99) and a corresponding "control group" ([CG]: n = 80) were investigated with regard to zinc tolerance, antimicrobial- and biocide susceptibilities by determining minimum inhibitory concentrations (MICs). In addition, in silico whole genome screening (WGSc) for antibiotic resistance genes (ARGs) as well as biocide- and heavy metal tolerance genes was performed using an in-house BLAST-based pipeline. Overall, porcine E. coli isolates showed three different ZnCl2 MICs: 128 μg/ml (HZG, 2%; CG, 6%), 256 μg/ml (HZG, 64%; CG, 91%) and 512 μg/ml ZnCl2 (HZG, 34%, CG, 3%), a unimodal distribution most likely reflecting natural differences in zinc tolerance associated with different genetic lineages. However, a selective impact of the zinc-rich supplemented diet seems to be reasonable, since the linear mixed regression model revealed a statistically significant association between "higher" ZnCl2 MICs and isolates representing the HZG as well as "lower ZnCl2 MICs" with isolates of the CG (p = 0.005). None of the zinc chloride MICs was associated with a particular antibiotic-, heavy metal- or biocide- tolerance/resistance phenotype. Isolates expressing the 512 μg/ml MIC were either positive for ARGs conferring resistance to aminoglycosides, tetracycline and sulfamethoxazole-trimethoprim, or harbored no ARGs at all. Moreover, WGSc revealed a ubiquitous presence of zinc homeostasis and - detoxification genes, including zitB, zntA, and pit. In conclusion, we provide evidence that zinc-rich supplementation of pig feed selects for more zinc tolerant E. coli, including isolates harboring ARGs and biocide- and heavy metal tolerance genes - a putative selective advantage considering substances and antibiotics currently used in industrial pork production systems.
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Affiliation(s)
- Vanessa C Johanns
- Advanced Light and Electron Microscopy (ZBS-4), Robert Koch Institute, Berlin, Germany
| | - Fereshteh Ghazisaeedi
- Institute of Microbiology and Epizootics, Centre for Infection Medicine, Freie Universität Berlin, Berlin, Germany
| | - Lennard Epping
- Microbial Genomics (NG1), Robert Koch Institute, Berlin, Germany
| | - Torsten Semmler
- Microbial Genomics (NG1), Robert Koch Institute, Berlin, Germany
| | - Antina Lübke-Becker
- Institute of Microbiology and Epizootics, Centre for Infection Medicine, Freie Universität Berlin, Berlin, Germany
| | - Yvonne Pfeifer
- Nosocomial Pathogens and Antibiotic Resistances, Robert Koch Institute, Wernigerode, Germany
| | - Astrid Bethe
- Institute of Microbiology and Epizootics, Centre for Infection Medicine, Freie Universität Berlin, Berlin, Germany
| | - Inga Eichhorn
- Institute of Microbiology and Epizootics, Centre for Infection Medicine, Freie Universität Berlin, Berlin, Germany
| | - Roswitha Merle
- Institute for Veterinary Epidemiology and Biostatistics, Freie Universität Berlin, Berlin, Germany
| | - Birgit Walther
- Advanced Light and Electron Microscopy (ZBS-4), Robert Koch Institute, Berlin, Germany
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Neupane DP, Fullam SH, Chacón KN, Yukl ET. Crystal structures of AztD provide mechanistic insights into direct zinc transfer between proteins. Commun Biol 2019; 2:308. [PMID: 31428696 PMCID: PMC6689063 DOI: 10.1038/s42003-019-0542-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 07/15/2019] [Indexed: 12/19/2022] Open
Abstract
Zinc acquisition from limited environments is critical for bacterial survival and pathogenesis. AztD has been identified as a periplasmic or cell surface zinc-binding protein in numerous bacterial species. In Paracoccus denitrificans, AztD can transfer zinc directly to AztC, the solute binding protein for a zinc-specific ATP-binding cassette transporter system, suggesting a role in zinc acquisition and homeostasis. Here, we present the first cry stal structures of AztD from P. denitrificans and tbe human pathogen Citrobacter koseri, revealing a beta-propeller fold and two high-affinity zinc-binding sites that are highly conserved among AztD homologs. These structures combined with transfer assays using WT and mutant proteins provide rare insight into the mechanism of direct zinc transfer from one protein to another. Given the importance of zinc import to bacterial pathogenesis, these insights may prove valuable to the development of zinc transfer inhibitors as antibiotics.
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Affiliation(s)
- Durga Prasad Neupane
- Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, NM 88003 USA
| | - Stephanie Hope Fullam
- Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, NM 88003 USA
| | | | - Erik Thomas Yukl
- Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, NM 88003 USA
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Ferretti MB, Karbstein K. Does functional specialization of ribosomes really exist? RNA (NEW YORK, N.Y.) 2019; 25:521-538. [PMID: 30733326 PMCID: PMC6467006 DOI: 10.1261/rna.069823.118] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
It has recently become clear that ribosomes are much more heterogeneous than previously thought, with diversity arising from rRNA sequence and modifications, ribosomal protein (RP) content and posttranslational modifications (PTMs), as well as bound nonribosomal proteins. In some cases, the existence of these diverse ribosome populations has been verified by biochemical or structural methods. Furthermore, knockout or knockdown of RPs can diversify ribosome populations, while also affecting the translation of some mRNAs (but not others) with biological consequences. However, the effects on translation arising from depletion of diverse proteins can be highly similar, suggesting that there may be a more general defect in ribosome function or stability, perhaps arising from reduced ribosome numbers. Consistently, overall reduced ribosome numbers can differentially affect subclasses of mRNAs, necessitating controls for specificity. Moreover, in order to study the functional consequences of ribosome diversity, perturbations including affinity tags and knockouts are introduced, which can also affect the outcome of the experiment. Here we review the available literature to carefully evaluate whether the published data support functional diversification, defined as diverse ribosome populations differentially affecting translation of distinct mRNA (classes). Based on these observations and the commonly observed cellular responses to perturbations in the system, we suggest a set of important controls to validate functional diversity, which should include gain-of-function assays and the demonstration of inducibility under physiological conditions.
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Affiliation(s)
- Max B Ferretti
- Department of Integrative Structural and Molecular Biology, The Scripps Research Institute, Jupiter, Florida 33458, USA
- The Skaggs Graduate School of Chemical and Biological Sciences, The Scripps Research Institute, Jupiter, Florida 33458, USA
| | - Katrin Karbstein
- Department of Integrative Structural and Molecular Biology, The Scripps Research Institute, Jupiter, Florida 33458, USA
- The Skaggs Graduate School of Chemical and Biological Sciences, The Scripps Research Institute, Jupiter, Florida 33458, USA
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39
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Bacterial ribosome heterogeneity: Changes in ribosomal protein composition during transition into stationary growth phase. Biochimie 2019; 156:169-180. [DOI: 10.1016/j.biochi.2018.10.013] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 10/18/2018] [Indexed: 12/11/2022]
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40
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Gaulke CA, Rolshoven J, Wong CP, Hudson LG, Ho E, Sharpton TJ. Marginal Zinc Deficiency and Environmentally Relevant Concentrations of Arsenic Elicit Combined Effects on the Gut Microbiome. mSphere 2018; 3:e00521-18. [PMID: 30518676 PMCID: PMC6282007 DOI: 10.1128/msphere.00521-18] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 10/30/2018] [Indexed: 01/16/2023] Open
Abstract
Extensive research shows that dietary variation and toxicant exposure impact the gut microbiome, yielding effects on host physiology. However, prior work has mostly considered such exposure-microbiome interactions through the lens of single-factor exposures. In practice, humans exposed to toxicants vary in their dietary nutritional status, and this variation may impact subsequent exposure of the gut microbiome. For example, chronic arsenic exposure affects 200 million people globally and is often comorbid with zinc deficiency. Zinc deficiency can enhance arsenic toxicity, but it remains unknown how zinc status impacts the gut microbiome's response to arsenic exposure and whether this response links to host toxicity. Using 16S amplicon sequencing, we examined the combinatorial effects of exposure to environmentally relevant concentrations of arsenic on the composition of the microbiome in C57BL/6 mice fed diets varying in zinc concentration. Arsenic exposure and marginal zinc deficiency independently altered microbiome diversity. When combined, their effects on microbiome community structure were amplified. Generalized linear models identified microbial taxa whose relative abundance in the gut was perturbed by zinc deficiency, arsenic, or their interaction. Further, we correlated taxonomic abundances with host DNA damage, adiponectin expression, and plasma zinc concentration to identify taxa that may mediate host physiological responses to arsenic exposure or zinc deficiency. Arsenic exposure and zinc restriction also result in increased DNA damage and decreased plasma zinc. These physiological changes are associated with the relative abundance of several gut taxa. These data indicate that marginal zinc deficiency sensitizes the microbiome to arsenic exposure and that the microbiome associates with some toxicological effects of arsenic.IMPORTANCE Xenobiotic compounds, such as arsenic, have the potential to alter the composition and functioning of the gut microbiome. The gut microbiome may also interact with these compounds to mediate their impact on the host. However, little is known about how dietary variation may reshape how the microbiome responds to xenobiotic exposures or how these modified responses may in turn impact host physiology. Here, we investigated the combinatorial effects of marginal zinc deficiency and physiologically relevant concentrations of arsenic on the microbiome. Both zinc deficiency and arsenic exposure were individually associated with altered microbial diversity and when combined elicited synergistic effects. Microbial abundance also covaried with host physiological changes, indicating that the microbiome may contribute to or be influenced by these pathologies. Collectively, this work demonstrates that dietary zinc intake influences the sensitivity of the microbiome to subsequent arsenic exposure.
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Affiliation(s)
| | - John Rolshoven
- School of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon, USA
| | - Carmen P Wong
- School of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon, USA
| | - Laurie G Hudson
- Department of Pharmaceutical Sciences, University of New Mexico, Albuquerque, New Mexico, USA
| | - Emily Ho
- School of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon, USA
- Linus Pauling Institute, Oregon State University, Corvallis, Oregon, USA
- Moore Family Center for Whole Grain Foods, Nutrition and Preventive Health, Oregon State University, Corvallis, Oregon, USA
| | - Thomas J Sharpton
- Department of Microbiology, Oregon State University, Corvallis, Oregon, USA
- Department of Statistics, Oregon State University, Corvallis, Oregon, USA
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41
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Neupane DP, Kumar S, Yukl ET. Two ABC Transporters and a Periplasmic Metallochaperone Participate in Zinc Acquisition in Paracoccus denitrificans. Biochemistry 2018; 58:126-136. [PMID: 30353723 PMCID: PMC6824839 DOI: 10.1021/acs.biochem.8b00854] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
![]()
Bacteria must acquire the essential
element zinc from extremely
limited environments, and this function is performed largely by ATP
binding cassette (ABC) transporters. These systems rely on a periplasmic
or extracellular solute binding protein (SBP) to bind zinc specifically
with a high affinity and deliver it to the membrane permease for import
into the cytoplasm. However, zinc acquisition systems in bacteria
may be more complex, involving multiple transporters and other periplasmic
or extracellular zinc binding proteins. Here we describe the zinc
acquisition functions of two zinc SBPs (ZnuA and AztC) and a novel
periplasmic metallochaperone (AztD) in Paracoccus denitrificans. ZnuA was characterized in vitro and demonstrated
to bind as many as 5 zinc ions with a high affinity. It does not interact
with AztD, in contrast to what has been demonstrated for AztC, which
is able to acquire a single zinc ion through associative transfer
from AztD. Deletions of the corresponding genes singly and in combination
show that either AztC or ZnuA is sufficient and essential for robust
growth in zinc-limited media. Although AztD cannot support transport
of zinc into the cytoplasm, it likely functions to store zinc in the
periplasm for transfer through the AztABCD system.
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Affiliation(s)
- Durga P Neupane
- Department of Chemistry and Biochemistry , New Mexico State University , Las Cruces , New Mexico 88003 , United States
| | - Santosh Kumar
- Department of Biological Sciences , University of Texas at Dallas , Richardson , Texas 75080 , United States
| | - Erik T Yukl
- Department of Chemistry and Biochemistry , New Mexico State University , Las Cruces , New Mexico 88003 , United States
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42
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Bobrov AG, Kirillina O, Fosso MY, Fetherston JD, Miller MC, VanCleave TT, Burlison JA, Arnold WK, Lawrenz MB, Garneau-Tsodikova S, Perry RD. Zinc transporters YbtX and ZnuABC are required for the virulence of Yersinia pestis in bubonic and pneumonic plague in mice. Metallomics 2018; 9:757-772. [PMID: 28540946 DOI: 10.1039/c7mt00126f] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
A number of bacterial pathogens require the ZnuABC Zinc (Zn2+) transporter and/or a second Zn2+ transport system to overcome Zn2+ sequestration by mammalian hosts. Previously we have shown that in addition to ZnuABC, Yersinia pestis possesses a second Zn2+ transporter that involves components of the yersiniabactin (Ybt), siderophore-dependent iron transport system. Synthesis of the Ybt siderophore and YbtX, a member of the major facilitator superfamily, are both critical components of the second Zn2+ transport system. Here we demonstrate that a ybtX znu double mutant is essentially avirulent in mouse models of bubonic and pneumonic plague while a ybtX mutant retains high virulence in both plague models. While sequestration of host Zn is a key nutritional immunity factor, excess Zn appears to have a significant antimicrobial role in controlling intracellular bacterial survival. Here, we demonstrate that ZntA, a Zn2+ exporter, plays a role in resistance to Zn toxicity in vitro, but that a zntA zur double mutant retains high virulence in both pneumonic and bubonic plague models and survival in macrophages. We also confirm that Ybt does not directly bind Zn2+in vitro under the conditions tested. However, we detect a significant increase in Zn2+-binding ability of filtered supernatants from a Ybt+ strain compared to those from a strain unable to produce the siderophore, supporting our previously published data that Ybt biosynthetic genes are involved in the production of a secreted Zn-binding molecule (zincophore). Our data suggest that Ybt or a modified Ybt participate in or promote Zn-binding activity in culture supernatants and is involved in Zn acquisition in Y. pestis.
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Affiliation(s)
- Alexander G Bobrov
- Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky, Lexington, KY, USA.
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43
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Southam HM, Smith TW, Lyon RL, Liao C, Trevitt CR, Middlemiss LA, Cox FL, Chapman JA, El-Khamisy SF, Hippler M, Williamson MP, Henderson PJF, Poole RK. A thiol-reactive Ru(II) ion, not CO release, underlies the potent antimicrobial and cytotoxic properties of CO-releasing molecule-3. Redox Biol 2018; 18:114-123. [PMID: 30007887 PMCID: PMC6067063 DOI: 10.1016/j.redox.2018.06.008] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 06/23/2018] [Indexed: 12/25/2022] Open
Abstract
Carbon monoxide (CO)-releasing molecules (CORMs), mostly metal carbonyl compounds, are extensively used as experimental tools to deliver CO, a biological ‘gasotransmitter’, in mammalian systems. CORMs are also explored as potential novel antimicrobial drugs, effectively and rapidly killing bacteria in vitro and in animal models, but are reportedly benign towards mammalian cells. Ru-carbonyl CORMs, exemplified by CORM-3 (Ru(CO)3Cl(glycinate)), exhibit the most potent antimicrobial effects against Escherichia coli. We demonstrate that CORM-3 releases little CO in buffers and cell culture media and that the active antimicrobial agent is Ru(II), which binds tightly to thiols. Thus, thiols and amino acids in complex growth media – such as histidine, methionine and oxidised glutathione, but most pertinently cysteine and reduced glutathione (GSH) – protect both bacterial and mammalian cells against CORM-3 by binding and sequestering Ru(II). No other amino acids exert significant protective effects. NMR reveals that CORM-3 binds cysteine and GSH in a 1:1 stoichiometry with dissociation constants, Kd, of about 5 μM, while histidine, GSSG and methionine are bound less tightly, with Kd values ranging between 800 and 9000 μM. There is a direct positive correlation between protection and amino acid affinity for CORM-3. Intracellular targets of CORM-3 in both bacterial and mammalian cells are therefore expected to include GSH, free Cys, His and Met residues and any molecules that contain these surface-exposed amino acids. These results necessitate a major reappraisal of the biological effects of CORM-3 and related CORMs. Carbon monoxide-releasing molecules (CORMs) are used for experimental CO delivery. CORM-3 is a potent antimicrobial, but is reportedly beneficial to mammalian cells. We demonstrate CORM-3 releases little CO in buffers and cell culture media. Redox-active Ru2+ is the biological agent, binding tightly to metabolites e.g. thiol. These results necessitate a major reappraisal of the biological effects of CORMs.
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Affiliation(s)
- Hannah M Southam
- Department of Molecular Biology and Biotechnology, The University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Thomas W Smith
- Department of Chemistry, The University of Sheffield, Western Bank, Sheffield S3 7HF, UK
| | - Rhiannon L Lyon
- Department of Molecular Biology and Biotechnology, The University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Chunyan Liao
- Department of Molecular Biology and Biotechnology, The University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Clare R Trevitt
- Department of Molecular Biology and Biotechnology, The University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Laurence A Middlemiss
- Department of Chemistry, The University of Sheffield, Western Bank, Sheffield S3 7HF, UK
| | - Francesca L Cox
- Department of Chemistry, The University of Sheffield, Western Bank, Sheffield S3 7HF, UK
| | - Jonathan A Chapman
- Department of Chemistry, The University of Sheffield, Western Bank, Sheffield S3 7HF, UK
| | - Sherif F El-Khamisy
- Department of Molecular Biology and Biotechnology, The University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Michael Hippler
- Department of Chemistry, The University of Sheffield, Western Bank, Sheffield S3 7HF, UK
| | - Michael P Williamson
- Department of Molecular Biology and Biotechnology, The University of Sheffield, Western Bank, Sheffield S10 2TN, UK.
| | - Peter J F Henderson
- School of Biomedical Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, UK.
| | - Robert K Poole
- Department of Molecular Biology and Biotechnology, The University of Sheffield, Western Bank, Sheffield S10 2TN, UK.
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44
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Dow A, Prisic S. Alternative ribosomal proteins are required for growth and morphogenesis of Mycobacterium smegmatis under zinc limiting conditions. PLoS One 2018; 13:e0196300. [PMID: 29684089 PMCID: PMC5912738 DOI: 10.1371/journal.pone.0196300] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Accepted: 04/10/2018] [Indexed: 01/19/2023] Open
Abstract
Zinc is an essential micronutrient required for proper structure and function of many proteins. Bacteria regularly encounter zinc depletion and have evolved diverse mechanisms to continue growth when zinc is limited, including the expression of zinc-independent paralogs of zinc-binding proteins. Mycobacteria have a conserved operon encoding four zinc-independent alternative ribosomal proteins (AltRPs) that are expressed when zinc is depleted. It is unknown if mycobacterial AltRPs replace their primary paralogs in the ribosome and maintain protein synthesis under zinc-limited conditions, and if such replacements contribute to their physiology. This study shows that AltRPs from Mycobacterium smegmatis are essential for growth when zinc ion is scarce. Specifically, the deletion mutant of this operon (ΔaltRP) is unable to grow in media containing a high-affinity zinc chelator, while growth of the wild type strain is unaffected under the same conditions. However, when zinc is gradually depleted during growth in zinc-limited medium, the ΔaltRP mutant maintains the same growth rate as seen for the wild type strain. In contrast to M. smegmatis grown with sufficient zinc supplementation that forms shorter cells when transitioning from logarithmic to stationary phase, M. smegmatis deficient for zinc elongates after the expression of AltRPs in late logarithmic phase. These zinc-depleted bacteria also exhibit a remarkable morphology characterized by a condensed chromosome, increased number of polyphosphate granules, and distinct appearance of lipid bodies and the cell wall compared to the zinc-replete cells. However, the ΔaltRP cells fail to elongate and transition into the zinc-limited morphotype, resembling the wild type zinc-replete bacteria instead. Therefore, the altRP operon in M. smegmatis has a vital role in continuation of growth when zinc is scarce and in triggering specific morphogenesis during the adaptation to zinc limitation, suggesting that AltRPs can functionally replace their zinc-dependent paralogs, but also contribute to mycobacterial physiology in a unique way.
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Affiliation(s)
- Allexa Dow
- Department of Microbiology, University of Hawai‛i at Mānoa, Honolulu, Hawai‛i, United States of America
| | - Sladjana Prisic
- Department of Microbiology, University of Hawai‛i at Mānoa, Honolulu, Hawai‛i, United States of America
- * E-mail:
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45
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Chen J, Wang L, Shang F, Dong Y, Ha NC, Nam KH, Quan C, Xu Y. Crystal structure of E. coli ZinT with one zinc-binding mode and complexed with citrate. Biochem Biophys Res Commun 2018; 500:139-144. [PMID: 29596824 DOI: 10.1016/j.bbrc.2018.03.192] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 03/25/2018] [Indexed: 12/31/2022]
Abstract
The ZnuABC ATP-binding cassette transporter found in gram-negative bacteria has been implicated in ensuring adequate zinc import into Zn(II)-poor environments. ZinT is an essential component of ZnuABC and contributes to metal transport by transferring metals to ZnuA, which delivers them to ZnuB in periplasmic zinc recruitment. Although several structures of E. coli ZinT have been reported, its zinc-binding sites and oligomeric state have not been clearly identified. Here, we report the crystal structure of E. coli ZinT at 1.76 Å resolution. This structure contains one zinc ion in its calycin-like domain, and this ion is coordinated by three highly conserved histidine residues (His167, His176 and His178). Moreover, three oxygen atoms (O1, O6 and O7) from the citrate molecule interact with zinc, giving the zinc ion stable octahedral coordination. Our EcZinT structure shows the fewest zinc ions bound of all reported EcZinT structures. Crystallographic packing and size exclusion chromatography suggest that EcZinT prefers to form monomers in solution. Our results provide insights into the molecular function of ZinT.
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Affiliation(s)
- Jinli Chen
- Department of Bioengineering, College of Life Science, Dalian Minzu University, Dalian 116600, Liaoning, China; Key Laboratory of Biotechnology and Bioresources Utilization (Dalian Minzu University), Ministry of Education, China
| | - Lulu Wang
- Department of Bioengineering, College of Life Science, Dalian Minzu University, Dalian 116600, Liaoning, China; Key Laboratory of Biotechnology and Bioresources Utilization (Dalian Minzu University), Ministry of Education, China; School of Life Science and Biotechnology, Dalian University of Technology, No 2 Linggong Road, Dalian 116024, Liaoning, China
| | - Fei Shang
- Department of Bioengineering, College of Life Science, Dalian Minzu University, Dalian 116600, Liaoning, China; Key Laboratory of Biotechnology and Bioresources Utilization (Dalian Minzu University), Ministry of Education, China
| | - Yuesheng Dong
- School of Life Science and Biotechnology, Dalian University of Technology, No 2 Linggong Road, Dalian 116024, Liaoning, China
| | - Nam-Chul Ha
- Department of Agricultural Biotechnology, College of Agriculture and Life Sciences, Seoul National University, Gwanak-gu, Seoul 08826, Republic of Korea
| | - Ki Hyun Nam
- Division of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul 02841, Republic of Korea; Institute of Life Science and Natural Resources, Korea University, Seoul 02841, Republic of Korea.
| | - Chunshan Quan
- Department of Bioengineering, College of Life Science, Dalian Minzu University, Dalian 116600, Liaoning, China; Key Laboratory of Biotechnology and Bioresources Utilization (Dalian Minzu University), Ministry of Education, China.
| | - Yongbin Xu
- Department of Bioengineering, College of Life Science, Dalian Minzu University, Dalian 116600, Liaoning, China; Key Laboratory of Biotechnology and Bioresources Utilization (Dalian Minzu University), Ministry of Education, China.
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46
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Buracco S, Peracino B, Andreini C, Bracco E, Bozzaro S. Differential Effects of Iron, Zinc, and Copper on Dictyostelium discoideum Cell Growth and Resistance to Legionella pneumophila. Front Cell Infect Microbiol 2018; 7:536. [PMID: 29379774 PMCID: PMC5770829 DOI: 10.3389/fcimb.2017.00536] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 12/26/2017] [Indexed: 12/29/2022] Open
Abstract
Iron, zinc, and copper play fundamental roles in eucaryotes and procaryotes, and their bioavailability regulates host-pathogen interactions. For intracellular pathogens, the source of metals is the cytoplasm of the host, which in turn manipulates intracellular metal traffic following pathogen recognition. It is established that iron is withheld from the pathogen-containing vacuole, whereas for copper and zinc the evidence is unclear. Most infection studies in mammals have concentrated on effects of metal deficiency/overloading at organismal level. Thus, zinc deficiency or supplementation correlate with high risk of respiratory tract infection or recovery from severe infection, respectively. Iron, zinc, and copper deficiency or overload affects lymphocyte proliferation/maturation, and thus the adaptive immune response. Whether they regulate innate immunity at macrophage level is open, except for iron. The early identification in a mouse mutant susceptible to mycobacterial infection of the iron transporter Nramp1 allowed dissecting Nramp1 role in phagocytes, from the social amoeba Dictyostelium to macrophages. Nramp1 regulates iron efflux from the phagosomes, thus starving pathogenic bacteria for iron. Similar studies for zinc or copper are scant, due to the large number of copper and zinc transporters. In Dictyostelium, zinc and copper transporters include 11 and 6 members, respectively. To assess the role of zinc or copper in Dictyostelium, cells were grown under conditions of metal depletion or excess and tested for resistance to Legionella pneumophila infection. Iron shortage or overload inhibited Dictyostelium cell growth within few generations. Surprisingly, zinc or copper depletion failed to affect growth. Zinc or copper overloading inhibited cell growth at, respectively, 50- or 500-fold the physiological concentration, suggesting very efficient control of their homeostasis, as confirmed by Inductively Coupled Plasma Mass Spectrometry quantification of cellular metals. Legionella infection was inhibited or enhanced in cells grown under iron shortage or overload, respectively, confirming a major role for iron in controlling resistance to pathogens. In contrast, zinc and copper depletion or excess during growth did not affect Legionella infection. Using Zinpyr-1 as fluorescent sensor, we show that zinc accumulates in endo-lysosomal vesicles, including phagosomes, and the contractile vacuole. Furthermore, we provide evidence for permeabilization of the Legionella-containing vacuole during bacterial proliferation.
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Affiliation(s)
- Simona Buracco
- Department of Clinical and Biological Sciences, University of Torino, Turin, Italy
| | - Barbara Peracino
- Department of Clinical and Biological Sciences, University of Torino, Turin, Italy
| | - Claudia Andreini
- Magnetic Resonance Center (CERM), University of Florence, Florence, Italy
| | - Enrico Bracco
- Department of Oncology, University of Torino, Turin, Italy
| | - Salvatore Bozzaro
- Department of Clinical and Biological Sciences, University of Torino, Turin, Italy
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47
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The Components of the Unique Zur Regulon of Cupriavidus metallidurans Mediate Cytoplasmic Zinc Handling. J Bacteriol 2017; 199:JB.00372-17. [PMID: 28808127 DOI: 10.1128/jb.00372-17] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Accepted: 08/03/2017] [Indexed: 12/13/2022] Open
Abstract
Zinc is an essential trace element, yet it is toxic at high concentrations. In the betaproteobacterium Cupriavidus metallidurans, the highly efficient removal of surplus zinc from the periplasm is responsible for the outstanding metal resistance of the organism. Rather than having a typical Zur-dependent, high-affinity ATP-binding cassette transporter of the ABC protein superfamily for zinc uptake at low concentrations, C. metallidurans has the secondary zinc importer ZupT of the zinc-regulated transporter, iron-regulated transporter (ZRT/IRT)-like protein (ZIP) family. It is important to understand, therefore, how this zinc-resistant bacterium copes with exposure to low zinc concentrations. Members of the Zur regulon in C. metallidurans were identified by comparing the transcriptomes of a Δzur mutant and its parent strain. The consensus sequence of the Zur-binding box was derived for the zupTp promoter-regulatory region by use of a truncation assay. The motif was used to predict possible Zur boxes upstream of Zur regulon members. The binding of Zur to these boxes was confirmed. Two Zur boxes upstream of the cobW 1 gene, encoding a putative zinc chaperone, proved to be required for complete repression of cobW 1 and its downstream genes in cells cultivated in mineral salts medium. A Zur box upstream of each of zur-cobW 2, cobW 3, and zupT permitted both low expression levels of these genes and their upregulation under conditions of zinc starvation. This demonstrates a compartmentalization of zinc homeostasis in C. metallidurans, where the periplasm is responsible for the removal of surplus zinc, cytoplasmic components are responsible for the management of zinc as an essential cofactor, and the two compartments are connected by ZupT.IMPORTANCE Elucidating zinc homeostasis is necessary for understanding both host-pathogen interactions and the performance of free-living bacteria in their natural environments. Escherichia coli acquires zinc under conditions of low zinc concentrations via the Zur-controlled ZnuABC importer of the ABC superfamily, and this was also the paradigm for other bacteria. In contrast, the heavy-metal-resistant bacterium C. metallidurans achieves high tolerance to zinc through sophisticated zinc handling and efflux systems operating on periplasmic zinc ions, so that removal of surplus zinc is a periplasmic feature in this bacterium. It is shown here that this process is augmented by the management of zinc by cytoplasmic zinc chaperones, whose synthesis is controlled by the Zur regulator. This demonstrates a new mechanism, involving compartmentalization, for organizing zinc homeostasis.
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48
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Neupane DP, Avalos D, Fullam S, Roychowdhury H, Yukl ET. Mechanisms of zinc binding to the solute-binding protein AztC and transfer from the metallochaperone AztD. J Biol Chem 2017; 292:17496-17505. [PMID: 28887302 DOI: 10.1074/jbc.m117.804799] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Revised: 08/16/2017] [Indexed: 01/22/2023] Open
Abstract
Bacteria can acquire the essential metal zinc from extremely zinc-limited environments by using ATP-binding cassette (ABC) transporters. These transporters are critical virulence factors, relying on specific and high-affinity binding of zinc by a periplasmic solute-binding protein (SBP). As such, the mechanisms of zinc binding and release among bacterial SBPs are of considerable interest as antibacterial drug targets. Zinc SBPs are characterized by a flexible loop near the high-affinity zinc-binding site. The function of this structure is not always clear, and its flexibility has thus far prevented structural characterization by X-ray crystallography. Here, we present intact structures for the zinc-specific SBP AztC from the bacterium Paracoccus denitrificans in the zinc-bound and apo-states. A comparison of these structures revealed that zinc loss prompts significant structural rearrangements, mediated by the formation of a sodium-binding site in the apo-structure. We further show that the AztC flexible loop has no impact on zinc-binding affinity, stoichiometry, or protein structure, yet is essential for zinc transfer from the metallochaperone AztD. We also found that 3 His residues in the loop appear to temporarily coordinate zinc and then convey it to the high-affinity binding site. Thus, mutation of any of these residues to Ala abrogated zinc transfer from AztD. Our structural and mechanistic findings conclusively identify a role for the AztC flexible loop in zinc acquisition from the metallochaperone AztD, yielding critical insights into metal binding by AztC from both solution and AztD. These proteins are highly conserved in human pathogens, making this work potentially useful for the development of novel antibiotics.
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Affiliation(s)
- Durga P Neupane
- From the Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, New Mexico 88003
| | - Dante Avalos
- From the Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, New Mexico 88003
| | - Stephanie Fullam
- From the Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, New Mexico 88003
| | - Hridindu Roychowdhury
- From the Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, New Mexico 88003
| | - Erik T Yukl
- From the Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, New Mexico 88003
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49
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Despotović D, Brandis A, Savidor A, Levin Y, Fumagalli L, Tawfik DS. Diadenosine tetraphosphate (Ap4A) - an E. coli alarmone or a damage metabolite? FEBS J 2017; 284:2194-2215. [PMID: 28516732 DOI: 10.1111/febs.14113] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 05/15/2017] [Indexed: 12/21/2022]
Abstract
Under stress, metabolism is changing: specific up- or down-regulation of proteins and metabolites occurs as well as side effects. Distinguishing specific stress-signaling metabolites (alarmones) from side products (damage metabolites) is not trivial. One example is diadenosine tetraphosphate (Ap4A) - a side product of aminoacyl-tRNA synthetases found in all domains of life. The earliest observations suggested that Ap4A serves as an alarmone for heat stress in Escherichia coli. However, despite 50 years of research, the signaling mechanisms associated with Ap4A remain unknown. We defined a set of criteria for distinguishing alarmones from damage metabolites to systematically classify Ap4A. In a nutshell, no indications for a signaling cascade that is triggered by Ap4A were found; rather, we found that Ap4A is efficiently removed in a constitutive, nonregulated manner. Several fold perturbations in Ap4A concentrations have no effect, yet accumulation at very high levels is toxic due to disturbance of zinc homeostasis, and also because Ap4A's structural overlap with ATP can result in spurious binding and inactivation of ATP-binding proteins. Overall, Ap4A met all criteria for a damage metabolite. While we do not exclude any role in signaling, our results indicate that the damage metabolite option should be considered as the null hypothesis when examining Ap4A and other metabolites whose levels change upon stress.
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Affiliation(s)
- Dragana Despotović
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Alexander Brandis
- Life Sciences Core Facilities, Weizmann Institute of Science, Rehovot, Israel
| | - Alon Savidor
- Nancy and Stephen Grand Israel National Center for Personalized Medicine, Weizmann Institute of Science, Rehovot, Israel
| | - Yishai Levin
- Nancy and Stephen Grand Israel National Center for Personalized Medicine, Weizmann Institute of Science, Rehovot, Israel
| | - Laura Fumagalli
- Dipartimento di Scienze Farmaceutiche, Università degli Studi di Milano, Italy
| | - Dan S Tawfik
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
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50
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Neupane DP, Jacquez B, Sundararajan A, Ramaraj T, Schilkey FD, Yukl ET. Zinc-Dependent Transcriptional Regulation in Paracoccus denitrificans. Front Microbiol 2017; 8:569. [PMID: 28443074 PMCID: PMC5387054 DOI: 10.3389/fmicb.2017.00569] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 03/20/2017] [Indexed: 01/20/2023] Open
Abstract
Zinc homeostasis is critical for bacterial survival and is mediated largely at the transcriptional level by the regulation of zinc uptake and efflux genes. Here we use RNA-seq to assess transcriptional changes as a result of zinc limitation in the denitrifying bacterium Paracoccus denitrificans. The results identify the differential expression of 147 genes, most of which were upregulated in zinc-depleted medium. Included in this set of genes are a large number of transition metal transporters, several transcription factors, and hypothetical proteins. Intriguingly, genes encoding nitric oxide reductase (norCB) and nitrite reductase (nirS) were also upregulated. A Zur consensus binding motif was identified in the promoters of the most highly upregulated genes. The zinc uptake regulator (Zur) from this organism was also characterized and shown to bind to the Zur motif in a zinc-dependent manner. This work expands our current understanding of the transcriptional response of gram-negative bacteria to zinc limitation and identifies genes involved in denitrification as part of the Zur regulon.
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Affiliation(s)
- Durga P Neupane
- Department of Chemistry and Biochemistry, New Mexico State UniversityLas Cruces, NM, USA
| | - Belkis Jacquez
- Department of Chemistry and Biochemistry, New Mexico State UniversityLas Cruces, NM, USA
| | | | | | | | - Erik T Yukl
- Department of Chemistry and Biochemistry, New Mexico State UniversityLas Cruces, NM, USA
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